Downloaded By: [Du, K.] At: 00:06 31 October 2007 h rsneo ri onayfls[1 5 7.Hwvr Lee However, 17]. 15, [11, demonstrate films to boundary failed grain (TEM) of microscopy presence electron the transmission by titanates barium [8–16]. compounds titanate barium of behaviour Crepnigato.Eal [email protected] Email: author. *Corresponding BaTiO Introduction 1. 5447–5459 2007, December 1 34, No. 87, Vol. Magazine Philosophical Ba irwv eie 13.Freape -oe BaTiO Y-doped example, tuneable For and [1–3]. capacitors ceramic devices multilayer sensors, microwave in applications numerous have onais(B)[–] nesv tde aebe efre nteG structures GB the on performed been BaTiO have in studies Intensive [4–7]. (GBs) boundaries mgs sn mrhu hs a on ntersml n h sintering the and sample their in found was phase (EELS). HRTEM amorphous (1250 from spectroscopy temperature resolved no not loss was As phase intermediate electron-energy images. the of and structure the (HRTEM) Nonetheless, microscopy electron nemdaepaewt oia opsto fBaTi of composition nominal a with phase intermediate bomlgangot ihTiO with growth grain abnormal omriltemsos ti eeal cetdta h lcrclpoete fthe as of properties used electrical widely the are that accepted (PTC), generally BaTiO resistivity is It of thermistors. coefficient commercial temperature positive excellent 6 Ti lhuhganbudr im omnyocri eais otsuison studies most ceramics, in occur commonly films boundary grain Although y hnagNtoa aoaoyfrMtrasSine nttt fMtlResearch, Metal of Institute Science, Materials for Laboratory National Shenyang ealdsrcueo h nefc ewe BaTiO between interface the of structure detailed eemndbtentettaoa BaTiO tetragonal the between determined itrdblwteetci eprtr nar h ae osse crystal a possessed layer The air. Ba in to temperature similar eutectic structure the below sintered ysann rnmsineeto irsoyadhg-eouintransmission high-resolution and investigations. microscopy microscopy electron electron transmission scanning by hsso Ba of phases retto eainhpof relationship orientation nitrrnlrlyrwsfudi . o%YdpdBaTiO Y-doped mol% 0.4 in found was layer intergranular An 17 E n TMivsiaino ri onaisand boundaries grain of investigation STEM and TEM 3 3 O bsdcmonsaeoeo h otiprateetoi eais which ceramics, electronic important most the of one are compounds -based hns cdm fSine,7 ehaRa,101 hnag China Shenyang, 110016 Road, Wenhua 72 Sciences, of Academy Chinese z eais atclrytePCefc,aecoeyrltdt hi grain their to related closely are effect, PTC the particularly ceramics, rdaeSho fCieeAaeyo cecs 009Biig China Beijing, 100049 Sciences, of Academy Chinese of School Graduate 3 40 eaisi h eeomn fmtrasadt nesadteelectrical the understand to and materials of development the in ceramics .J ZHENG J. S. 13 ) twspooe htteBaTiO the that proposed was it C), (1332 SN17–45pitIS 4864 online 1478–6443 print/ISSN 1478–6435 ISSN 6 )wswl eo h uetctmeaueo h eodphase second the of temperature eutectic the below well was C) Ti ( eodpae nbru titanate barium in phases second 17 eevd5Jn 07 nfnlfr 6Ags 2007 August 26 form final in 2007; June 5 Received O , 40 yz 6 eeas bevda rpeganjntosadan and junctions triple-grain at observed also were .DU* K. , Ti 17 O:10.1080/14786430701654386 DOI: ð http://www.tandf.co.uk/journals 1 O 1  1 2  40 hlspia Magazine Philosophical ecs BaTiO -excess Þ t == ihatikeso . m lt-iesecond Plate-like nm. 0.7 of thickness a with ð y 001 .H SANG H. X. , Þ m , 3 ð 1 n h oolncBa monoclinic the and 12  Þ 3 t == sn ihrslto transmission high-resolution using ß 3 ð 07Tyo Francis & Taylor 2007 60 n Ba and 3 yz 2  rishdanral grown abnormally had grains Þ 2 m O n .L MA L. X. and and 5 6 Ti tteGso BaTiO of GBs the at 3 17 ½ 110 ) eais ihtheir with ceramics, O 40 tal et 6 t 3 == Ti a resolved was hc was which , ½ 17 0 8 on an found [8] . 10 O  y 40 m The . was 3 in Downloaded By: [Du, K.] At: 00:06 31 October 2007 ttesm ae h nest fteiae sapoiaeypootoa othe to proportional the approximately collecting is images while ( the number axis mrad) of 60–227 atomic intensity of zone square range The angle mean the rate. an same (at in the detector HAADF at oriented the with specimens electrons transmitted crystalline the across codnl,iae fti yeaekonas known are type this of images Accordingly, 1,2–2.Nvrhls,al1 osbeoinainrltosis hc satisfy which relationships, orientation possible 12 all (111) Nevertheless, 20–22]. [18, TiO observed of 10] liquid GBs [9, a faceted co-workers at not and structure but Yamamoto ordered phase Similarly, an intermediate [8]. the believed of generally assistance as the phase with shape polyhedral a into 5448 oefgr nlsso oyrsaln Ba polycrystalline on analysis figure pole rsa BaTiO crystal -oe BaTiO Y-doped Experimental 2. o hmclaayi a bu nm. 1 annular about high-angle was a analysis plus chemical analysis for chemical for for detector a and (HAADF) system (EDS) dark-field (GIF) spectrometer filter dispersive energy imaging X-ray Gatan an with equipped was microscope 99 n 9,rsetvl,poie ySnpamCeia egn Ltd., Reagent Ba/Ti/Y Chemical of 1050 ratio Sinopharm at atomic calcined the by was at mixture mixed provided were China) respectively, Beijing, 99%, and 99.99 prpit mut fBaCO of amounts appropriate experiment. rsueo 0Ma h elt eete itrdi i t15 n 1300 and 1250 at air in sintered a then at mm) were 1 pellets thickness and The mm MPa. 20 20 (diameter of pellets pressure into dry-pressed were powders the mgn a mlydt eov h ealdsrcueo h ae swl sthe as well Z-contrast as high-resolution layer BaTiO and the the of material and structure phase the detailed second in the the resolve between intergranular GBs interface to An faceted employed (STEM). was at microscopy imaging found electron was transmission layer scanning and TEM n thdi H a polished were in specimens microscopy etched optical while and by ion-milling, prepared and were specimens grinding optical microscopy cutting, MEF4A Electron a Austria). and Wein, Japan) (Leica, JEM Tokyo, microscope a (JEOL, USA), microscope OR, electron Hillsboro, transmission Co., 2010 (FEI microscope electron transmission (scanning) otymaue as measured mostly uielk tutr yeeto osna-desrcue(LE)analysis. (ELNES) structure near-edge loss electron by structure rutile-like a 4ad1 .Tenmnlhaigadcoigrtswr 5 were rates cooling and heating nominal The h. 10 and 24 bevda B rcytldfcsisd arxgan 1–1.Teorientation The [18–21]. grains matrix BaTiO inside tetragonal defects the crystal between or relationship GBs at observed High-resolution nti ok ehv tde h B n eodpaei -oe BaTiO Y-doped a in phase second and GBs the studied have we work, this In h irsrcueo h oe BaTiO doped the of microstructure The nTiO In t //(001) 2 ecs BaTiO -excess m 3 usrt [23]. substrate and 3 a rprdb h ovninlmxdoiemto.The method. mixed-oxide conventional the by prepared was Z 2 /C/F(541 /)slto.TeTca 3 electron F30 Tecnai The solution. v/v) (95:4:1, O/HCl/HF ½ cnrs mgn spromdb cniga lcrnprobe electron an scanning by performed is imaging -contrast 1 ð 10  11  1  3 t == bsdcmons eodpaeBa phase second compounds, -based Þ t == ½ 010 o 0hadmle na gt otr Thereafter, mortar. agate an in milled and h 30 for C ð Z 001 3 TiO , ntevlmseaie yteeeto probe. electron the by examined volumes the in ) m Z .J Zheng J. S. Þ eeas eotdb -a diffraction X-ray by reported also were , cnrs mgn.Tesz fteeeto probe electron the of size The imaging. -contrast m , 2 ð 001 n Y and 2 Þ ecs BaTiO -excess t 6 == Ti 3 tal et ð 2 n h oolncBa monoclinic the and 17 3 10 O  O Z 3 . a tde sn eniF30 Tecnai a using studied was 1  40 cnrs mgs[4 5.A the As 25]. [24, images -contrast Þ odr wt uiiso 99.99, of purities (with powders 3 m grain. ecieyfre nasingle a on formed reactively ð 1 10  3 hc a sue obe to assumed was which , Þ ¼ t == .0:.0:.0.The 1.000:1.001:0.004. ð /i o h whole the for C/min 20 6 6 Ti  Þ m 17 , O ½ 6 001 40 Ti 17 a often was t O == over C 40 ½ 0 10  3 was by m Downloaded By: [Du, K.] At: 00:06 31 October 2007 ideo lt-ieanra ri.Ti aelei qixdanra risare grains abnormal equiaxed the in in located lamellae lamella Twin twin a grain. presents abnormal which arrows. plate-like A, by with indicated a marked of region the middle of enlargement an ris iue2)wr aee ihln emnsprle ote{1}pae and planes {111} the to BaTiO of parallel planes fine segments {110} normal, the long to and with parallel grains steps faceted small coarse were abnormal, 2a) figure between grains; boundaries (the GBs abnormal iue1sosatpclmcotutr fteYdpdBaTiO Y-doped the of microstructure typical a shows 1 Figure Results 3. from accuracy. retrieved high were a object functions at specimen specimens object the the 29], by the [28, Hence, of [24–27]. method convolution probe entropy Z incident maximum a the dark-field the as in of annular distribution use considered high-angle intensity be the using with can incoherent function as image treated the be detection, can signals collected BaTiO Y-doped of microstructure the showing micrograph Optical 1. Figure aeil rmtesneigsraetruhasre fdph ntesml tan at sample the in depths of series a a polishing 100 on through and of surface microscopy grinding increment by sintering optical a obtained the by were either from sections confirmed had the materials was Here, grains sections. which abnormal interior shape, of The series equiaxed sample. an the or in plate-like occurred growth grain abnormal n lcrnmcorps h vrg ieo h bomlgan a siae at estimated was grains abnormal more optical the or the of From one size other. contained average each often the to nonparallel micrographs, grains or electron shape parallel and be equiaxed elongated could the were which grains and lamellae, plate-like twin planes abnormal twin the the where grains, along abnormal the all nearly neg-nmti B hc eopsdit w ye ffct hs habit whose facets of types two shows into 3 decomposed figure example, which for GB, facets; form matrix also edge-on 2b) figure an grains; fine normal between cnrs mgst bantepstoa n nest nomto fteaosin atoms the of information intensity and positional the obtain to images -contrast 200 m oprdt arxgan of grains matrix to compared m m .Ti aele(niae yarw nfgr )cnb enin seen be can 1) figure in arrows by (indicated lamellae Twin m. E n TMivsiain nBaTiO in investigations STEM and TEM 0.3 m .TeTMsuyrvae htthe that revealed study TEM The m. 3 aymti B teboundaries (the GBs matrix Many . 3 ceramics 3 ti la that clear is It . 3 h ne is inset The . 5449 Downloaded By: [Du, K.] At: 00:06 31 October 2007 5450 iue3 ihrslto rnmsineeto irgah(RE)o faceted a of (HRTEM) micrograph electron transmission High-resolution GB. matrix 3. Figure GB abnormal faceted a of (TEM) (b). micrographs electron GB transmission matrix Bright-field and (a) 2. Figure .J Zheng J. S. tal et . Downloaded By: [Du, K.] At: 00:06 31 October 2007 n ii h eodpaewsblwtedtcinlmto h D analysis. EDS the of limit detection the below was phase second the in Si and Y h tutr oeso BaTiO of models structure the ieto sdfeet[2.Teeoe h mg nest aisi ifrn (001) different in varies intensity image the the in shown Therefore, as [22]. layers different is direction Ba and grain abnormal Ba a shows 4a Figure grains. {111} were planes oefvual o h {110} the for favourable more r ietyrltdt h aao oun ntemtra.I lal hw that, shows clearly image It the material. in spots {111} the bright the in the along columns (8), straight atom O being or Ba (22) of the Ti instead to either related than directly higher much are is (56) Ba of h APidctdprle lnsbtentettaoa BaTiO tetragonal the between planes parallel indicated SADP the aesot h {110} the onto facets ih (001) eight ½ h [321] the fgr d o h onayo h BaTiO the of boundary the for 5d) (figure ne lnsa h te side. other the at planes index eemndfo the from determined fteui elcnb eni h orsodn RE mg fgr 6). (figure image HRTEM corresponding the shape in actual seen the be although can time, cell acquisition unit long the the of during drift specimen constant ol o esml eae oteocpto fB tm 2,3] Nevertheless, scale. 31]. Ba local [24, a bulk atoms on of Ba applicable region could of remains the intensity occupation to effects, image Compared the the dechannelling to of related and interpretation qualitative simply scattering the be well of disordered not as intensity could boundary, as the the decrease such near or strain increase effects, of presence other the region, as boundary the at However, ewl s h aenme si 2]t eoete(001) the denote to [22] in as number same the use will we eodpaeisl rtue rmtepaa onayit h arxgan A triple- grains the the matrix from and taken Ba the was junction monoclinic 4b) into the figure triple-grain with boundary (SADP; junction pattern planar the grain diffraction and the select-area across shape A from B. plate-like straight protrudes and a runs itself Note has phase direction. boundary phase longitudinal second the second planar in The grain the abnormal C. the that grain with boundary abnormal planar an a forms and B, and A hl h aallai is axis parallel the while ½ itrino h ntcl fBa of cell unit the of distortion A ½ h onaybtenBaTiO between boundary the xs h ekrrfetoscm rmtescn hs n h togrreflections stronger the and phase BaTiO second abnormal the the from from came reflections weaker The axis. oolncBa monoclinic ucsie(001) successive retto eainhpwsdtrie for determined was relationship orientation 321 3 110 50  Z h Ba The h oolncui elo Ba of cell unit monoclinic The t t m cnrs mgn a efre ntepaa onaybtenteBaTiO the between boundary planar the on performed was imaging -contrast == == oeai fBa of axis zone ½ ½ 3 0 t 50 10   oeai fBaTiO of axis zone m 6 Ti m m aessakdaogte[001] the along stacked layers 17 scnitn ihti retto eainhp h ocnrto of concentration The relationship. orientation this with consistent is 6 m ewe BaTiO between Ti O aes h ubro aaosi h ntlnt ln the along length unit the in atoms Ba of number the layers, 40 17 t E n TMivsiain nBaTiO in investigations STEM and TEM n {110} and O eodpaewslctda rpejnto fteBaTiO the of junction triple a at located was phase second Z t 40 Z 6 n {001} and cnrs mg,adpaigteT n tm yfollowing by atoms O and Ti the placing and image, -contrast Ti hs aallpae are planes parallel These . ½ cnrs mg fteBa the of image -contrast 110 6 17 Ti 3 O ri tte[110] the at grain 17 t 40 6 == O t 3 Ti t 3 h orsodn AP(iue4)sgetdthat suggested 4c) (figure SADP corresponding The . fteBaTiO the of n {001} and 40 n Ba and ½ 3 0 17 3 sprle othe to parallel is t 10  lns hs tp niaeta ti energetically is it that indicate steps These planes. O n Ba and eodpae(iue5.A h tmcnumber atomic the As 5). (figure phase second n Ba and 6 40 Ti 6 m 6 Ti Ti 6 : eodpaestdbtentomti grains matrix two between sited phase second 17 Ti 6 h rpeganjnto a lotle othe to tilted also was junction triple-grain The 17 Ti 17 O Z 17 O t 6 O 17 t 40 cnrs mg;tu,teiaeintensity image the thus, image; -contrast Ti lnsta h {111} the than planes m O 40 ln fBaTiO of plane 40 O 6 Ti 40 t a ecniee sacntuto of construction a as considered be can 17 3 ieto sdsrbdi 2,3] Here, 30]. [22, in described as direction 3 40 tprgo ffgr ) tcnb seen be can it 5), figure of region (top oeai.Tecicdn elcin in reflections coincident The axis. zone nthe in O ri toesd fteG u high but GB the of side one at grain 17 eodpaetle othe to tilted phase second ri n Ba and grain sn h oriae fB atoms, Ba of coordinates the Using . ð 40 O 1 6 1  Ti tutr oe a deduced was model structure a , 40 1 ½  3 Þ hr h aallai of axis parallel the where , 17 50 t  ð == 1 Z O 1  cnrs mg sdet a to due is image -contrast ð m 40 1  3 001 Þ ceramics t fBa of ln the along m == 3 Þ h onayactually boundary the , aesi Ba in layers m 6 ð Ti 001 , 17 6 t ð Ti 1 Þ ln fBaTiO of plane O m 12  17 40 , ½ Þ 0 O t ð 10 ==  1 eodphase. second 40 12  ð ec,an Hence, . 6 m ½ 60 Ti 3 0 Þ t 10 direction.  == 2  17 n the and Þ m ð O m 60 ½ and , 0 40 zone 10  5451 2  .In 3 Þ m at m m 3 3 , Downloaded By: [Du, K.] At: 00:06 31 October 2007 fBaTiO of ri-ucin hr BaTiO where grain-junction, 5452 c directions. (c) Ba of image TEM Bright-field 4. Figure 3 ris() orsodn eetae ifato atrs(AP ftetriple the of (SADP) patterns diffraction select-area Corresponding (a). grains 3 ri a rettdt h [110] the to orientated was C grain .J Zheng J. S. 6 Ti 17 O 40 tal et eodpaelctda h rpejunction triple the at located phase second . t b n h [321] the and (b) t Downloaded By: [Du, K.] At: 00:06 31 October 2007 orsodn tutr models. structure corresponding onay hr h nefc sfctdaogte{001} the along open faceted topotactic by a by is as (marked indicated considered interface vacancies boundary, be Ba the could the of boundary where of the existence Nevertheless, boundary, vicinity the 5c). suggests the figure This in in circles 5b. missing figure are in spots arrows bright simulation some a is that inset The micrograph. 5. actual figure the in with shown well interface agrees same which the image, of image HRTEM HRTEM the of 6. Figure atoms. Ba method. the entropy of positions maximum the the shows only by (c) while restored interface, Ba image between the interface of The corresponding model Structure The (d) (b) High-resolution direction. (a) Ba 5. Figure tutr ssihl ifrn rmteitraesrcuepooe yKrasevec by proposed structure interface the from al different et slightly is structure BaTiO 6 Ti 2] hc sbsdo h ipecytlorpi osdrto httetwo the that consideration crystallographic simple the on based is which [22], . 17 3 O swl szgagdbten(001) between zigzagged as well as , 40 eodpaeadBaTiO and phase second E n TMivsiain nBaTiO in investigations STEM and TEM 6 Ti 17 O 40 n BaTiO and Z cnrs mg fteitraebtenthe between interface the of image -contrast 3 ri ae tteBaTiO the at taken grain 3 sidctdb izglnsi h mgsand images the in lines zigzag by indicated is m aes7ad8o Ba of 8 and 7 layers 3 ceramics 3 t ri ie ote[110] the to tiled grain n {110} and 6 Ti t 17 O lnsof planes 40 This . 5453 t Downloaded By: [Du, K.] At: 00:06 31 October 2007 onay b h orsodn mg etrdb h aiu nrp method. entropy shown. of are thickness maximum atoms Ba a the the possesses of which positions by the layer, only restored intergranular model; the the image in of marked corresponding model Structure The (c) (b) boundary. 5454 n {001} and BaTiO of the thickness a has layer by revealed phase-contrast for The severe surface more image. free are than the preparation, HRTEM imaging layer sample at TEM generated amorphous the during layer surface boundary amorphous the from the the and of particularly resolved delocalization specimen, contrast TEM be of the not of effects detailed the could the that although is boundary micrograph, reason high-resolution the the at structure with deduced well structure the agrees using it performed and was model simulation corresponding The 6). (figure {111} the at interface straight a with adjoined are phases High-resolution (a) 7. Figure tutr iia oBa to similar structure eevsbea h nefc ein u beta h onaybtenthe between boundary the at absent but region, interface the BaTiO at abnormal visible were eeldn pca nefc roinainrltosi ewe h intergranular the between BaTiO relationship fine orientation the or and interface layer special no revealed (001) osrcino h (001) the of construction eoaiain lhuhteitrrnlrlyrajie h tp nte{110} the contrast on inter- as steps such the the effects, adjoined although to layer due characteristics 8) intergranular (figure ordered the distinguishable Although exhibit hardly delocalization. is GBs layer the granular images, HRTEM nefc ewe h negaua ae n h bomlBaTiO abnormal the and layer intergranular the between interface nlssb lcrnsetocpciaig(S)rvae iecs at at Ti-excess EDS of revealed limit detection (ESI) the below imaging was concentration spectroscopic Si GBs. the GBs. electron abnormal the by analysis ewe h bomlBaTiO abnormal the between aeso h {001} the on facets (001) ttefctdanra B nteseie,itrrnlrlyr ol be could layers intergranular specimen, the in GBs abnormal faceted the At RE mg a lotkno h onayo BaTiO of boundary the on taken also was image HRTEM m m ae fBa of 7 layer aes7ad8o h Ba the of 8 and 7 layers t 3 lnso h BaTiO the of planes Z n h Ba the and Z cnrs mgn hnteGswr itdeg-n(iue7.This 7). (figure edge-on tilted were GBs the when imaging -contrast cnrs mgn ntevcnt fteboundary. the of vicinity the in imaging -contrast 3 ri n h Ba the and grain t 6 n {110} and Ti 17 6 Ti m O 6 3 Ti . m oprdwt h onaysrcuebetween structure boundary the with Compared nm. 0.7 40 ri tteohrsd fgr ) hmclcomposition Chemical 8). (figure side other the at grain 17 aes7 ,1 fBa of 2 1, 8, 7, layers 17 Z . O cnrs mg fa negaua ae faBaTiO a of layer intergranular an of image -contrast O 40 t 40 6 3 tcnb enta h negaua ae a a has layer intergranular the that seen be can it , lnso h BaTiO the of planes Ti 3 .J Zheng J. S. ri n h Ba the and grain 17 n httelyrcnb osdrda a as considered be can layer the that and toesd ftelyr h RE image HRTEM the layer, the of side one at O 6 Ti 40 17 tutr.Nvrhls,sm rgtspots bright some Nevertheless, structure. O 40 tal et eodpae ntecorresponding the In phase. second . 6 Ti 17 3 O 6 Ti n h izgbtenthe between zigzag the and 40 17 t iia oteboundary the to Similar . ln fBaTiO of plane O 40 eodpae the phase, second 3 3 n Ba and ri adjoined grain 3 . mas nm 0.7 6 n the and Ti 3 17 grain O 40 t Downloaded By: [Du, K.] At: 00:06 31 October 2007 ae fBaTiO of layer spots bright Periodic 7. figure in shown arrows. layer by intergranular indicated the are of interface image HRTEM the at 8. Figure Krasevec n nysihl -ergto ( Y-segregation slightly only and h nefc n h aee ofgrto f{100} of configuration faceted the and interface the lhuhahge oniec o R hnO1 hsidctsta ohO1and OR1 both that indicates This OR1. than OR2 for coincidence higher a although eefe.I a ese htteTiO the that seen be can It hereafter. eainhpof relationship iue9 hw ieve fteitraesrcuebtenBaTiO between structure interface the of view side a shows 9a Figure Discussion 4. is probe electron the of size the where measurement, icmtne,atog eragmn fteTiO the of rearrangement although circumstances, ð Ba nefc ytm 3–5.I a ese rmfgr caddta hr sahigh a is hetero- there that of d variety and a 9c figure to BaTiO from of applied seen points lattice be successfully the reciprocal can of been of coincidence It points has [33–35]. lattice systems model reciprocal the interface Their of crystals. proximity the two to interface. correspond the crystals at different formed are octahedra, face-shared i.e. elements, twin that edd sdsrbdi 2,3] o oprsn tutr oe fgr b fthe of 9b) (figure model structure a comparison, For 32]. BaTiO [22, in described as needed, 001 6 Ti stesml a oe ih04ml ,n -ihscn hs a observed was phase second Y-rich no Y, mol% 0.4 with doped was sample the As Pirouz Þ t == 17 3 O /Ba ð 10  40 1 tal et 6 [110] is direction viewing the where ,  tal et Ti Þ m 17 , 3 3]pooe htpeerdoinainrltosisbtentwo between relationships orientation preferred that proposed [33] . O ð 1 don h (001) the adjoins 2]ta h retto eainhpis relationship orientation the that [22] . ð 40 1  1 E n TMivsiain nBaTiO in investigations STEM and TEM 1  10  Þ t nefc a locntutdfloigtepooa of proposal the following constructed also was interface == Þ t == ð 001 ð 20 Þ 6 m Þ , m ð , 5 1 m 12  % tteGso BaTiO of GBs the at 1%) ½ ae fBa of 7 layer 110 Þ t 6 == caer eantesm retto across orientation same the retain octahedra ð t == 60 ½ 2  0 Þ 10  m and m 3 6 n Ba and Ti hneot R)adthe and OR2) (henceforth 6 t 17 caer nte(001) the in octahedra ½ t n {110} and 110 O fBaTiO of 40 nm. 1 3 6 t Ti ceramics == ttebudr.I shows It boundary. the at 17 ½ 0 3 O 10  t a eetdb EDS by detected was 40 sapial nthese in applicable is m 3 o R n OR2, and OR1 for h orientation The . sdntdOR1, denoted is ð 11  1  Þ t m == ln is plane ð 001 3 ð 11  5455 and Þ 1  m Þ t , Downloaded By: [Du, K.] At: 00:06 31 October 2007 orsodn lcrndfrcinpten.TiO patterns. diffraction electron corresponding Ba hc h eirclltiepit fBa of points lattice reciprocal the which pnadsldcrlsidct h eirclltiepit fcytlieBaTiO crystalline of points lattice reciprocal the indicate circles solid and Open niae yarrows. by indicated 5456 Al R;()ad()rpeetO2 h iwn ieto s[110] is direction viewing The OR2. represent (d) and (b) OR1; hc ersn nusal ragmn 3] ncnrs,O1hsteTiO is OR1 the therefore, has interface; OR1 the contrast, across orientation Ba In for same [32]. favourable the more arrangement in interface, unstable aligned the a at octahedra an important octahedra of face-shared an represent growth forms plays OR2 interface epitaxial [36]. which film/substrate energy the the interfacial of For total energy in 20–22]. the role [18, substrate, a found on mainly film thin was OR2 where more ceramics, Ba be may polycrystalline OR2 in while proved relationships, was orientation This favourable favourable. possibly are OR2 Ba between structures interface the of Schematics 9. Figure eeosre 2] swl si te tde nBa on studies other in as well as [23], observed were eoiino SiO of deposition hs a hti a lnrbudr ihte{111} the with boundary planar a had it that was phase spsil htteetci on a eraewt h rsneo muiis such impurities, of presence the with it decrease although may involved, SiO point phase as eutectic liquid the no that with formed possible was is phase second the that believed on riso BaTiO of grains round itrn elblwteetci eprtr fBaTiO of temperature eutectic the below well sintering Ba bevda rpejntoso h BaTiO the of junctions triple at observed eo h uetcpitadteS ocnrto sblwtedtcinlmto the of Ba of limit characteristic detection a the study, our below In is phase. concentration second the Si in the analysis and EDS point eutectic the below 2 6 6 Ti O Ti hnsneigwspromdaoeteetci eprtr fBaTiO of temperature eutectic the above performed was sintering When 3 17 17 2 O rSiO or O n Al and 40 40 epciey n()ad() ee a n c orsodt h tutr oe for model structure the to correspond (c) and (a) Here, (d). and (c) in respectively, , rsihl eo h uetcpitbtwt itne)adtvso CaO, of additives (intended) with but point eutectic the below slightly or 2 2 iudpaewsblee ofr n Ba and form to believed was phase liquid a , O 3 2 2,2] noreprmn,tesneigtmeaue(1300 temperature sintering the experiment, our In 21]. [20, nasnl rsa BaTiO crystal single a on 6 3 Ti 1,1,1] oee,Ba However, 19]. 18, [15, 17 O 40 hnfl ptxal rw nBaTiO on grown epitaxially film thin .J Zheng J. S. 6 Ti 3 17 riswt nagels hn60 than less angle an with grains 6 O caer r hatched are octahedra 40 3 tal et usrt,weebt R n OR2 and OR1 both where substrate, n BaTiO and . 6 Ti 6 6 Ti Ti 17 t 17 17 O ln fteanra grain abnormal the of plane 6 t 3 Ti fBaTiO of O O 40 n Ba and 3 17 40 40 eodpaei BaTiO in phase second r ihycicdn are coincident highly are O omdb chemical by formed , a loosre at observed also was 40 6 n BaTiO and per Ti 6 3 Ti n() h osin rows the (c), In . 17 2]i a n (b). and (a) in [22] 6 17 Ti O O 3 40 17 40 substrate. O a often was n tis it and , 40 3 n the and , between second 3 3 )is C) and and 6 3 Downloaded By: [Du, K.] At: 00:06 31 October 2007 ihrta hto Ti. of that than higher astase tatmeauejs eo hc h iudpaeapas as appears, phase liquid the Ba that which expect to below reasonable is just it of temperature Hence, mechanism [32]. a prevailing in the the suggested at of became surface transfer diffusion the on surface ions by mass as of formed diffusion sintering, not surface is during by the phase but particles at second phase planes the liquid indexed the that low of possible on solidification is faceted it not Therefore, were junction. grains triple-grain matrix two the grain; abnormal (at -oe BaTiO Y-doped h B scnitn ihtemdlo oiiebudr n eaiespace- negative and boundary positive a of Y model for reason the possible with Another consistent charge. is GBs the nemdaepaeasse h bomlgot fteBaTiO the of growth abnormal the assisted phase intermediate hswr hwta hr sn infcn ergto fY of of results segregation The significant no [7]. is space-charge there (partially) negative that presumably and show was work boundary and was this examined positive GB Ti-excess titanates the [7]. charge doped for microanalysis the positive responsible by of the GBs distinguishable all to hardly at are segregation observed regions donor and are two concentration slight the in the decrease charge) the core; the by by of effective magnitude compensation driven absolute hard (positive small possible is the donors region to the dopants owing of detect space-charge depletion donor to segregation, donor (negative negative acceptor the with dopants Compared the while positive depleted. acceptor a in potential, The of [7]. segregate electrostatic consisted space-charge charge) distribution negative for space-charge effective and The found GB significantly. charge only the segregated boundary barium were dopants that doped dopants acceptor was in although donor GBs interpretation GBs, that of at concluded composition segregation chemical and slight the titanates, measure strontium to and STEM used 39] [7, u h osbepeec falqi hs uigsneig stesintering the as sintering, in impurities during of existence phase 1, possible section the liquid in plus mentioned point a As eutectic material. rule the the of cannot to we close presence Nevertheless, is way. temperature possible similar a the in formed out be could layers intergranular tteGso TiO of GBs the at h ocnrto fY of concentration the TiO ein hssget htY that suggests This region. eeso Y of levels xesBaTiO excess ape sBOls yeaoaindrn itrn 4] sarsl,tesamples the result, a As [41]. sintering during TiO evaporation become by may loss BaO is samples opnainfo lcrn octo aace 4]o oteicroainof incorporation the to charge or of transition [44] additions BaTiO the vacancies dopant the to cation into either higher to dopants attributed at electrons was from suppressed inhibition compensation growth was Grain growth 43]. [42, grain while concentrations, ptxal ntesraeo BaTiO of surface the on epitaxially Y 3 þ bomlgangot a fe bevdi oe BaTiO doped in observed often was growth grain Abnormal m Y 2 tteBa the at ecs BaTiO -excess -btntaoi-cl)adapae lt-hpdo h usrt fthe of substrate the on plate-shaped appeared and atomic-scale) not but m- 3 þ rfrnilylctsa h Ba the at locates preferentially 2 O 3 2 3 þ 3] Xue [37]. eedpdit tihoercBaTiO stoichiometric into doped were 3 ie nBaTiO in sites 2 ape geswt rvosresults. previous with agrees samples ecs,atog h nta opsto f(Ba of composition initial the although -excess, E n TMivsiain nBaTiO in investigations STEM and TEM 3 ra h Ti the at or 2 ecs BaTiO -excess 3 þ tal et 3 tBa at atc 4] h bomlgangot bevdi the in observed growth grain abnormal The [43]. lattice 3 3]soe htY that showed [38] . þ 3 speoiatypeetteBa the present predominantly is 2 of þ 4 þ ie is sites 3 atc ie omn nacpo aini BaO- in cation acceptor an forming sites lattice . t 3,4] u bevto fT-xesat Ti-excess of observation Our 40]. [37, at% 1.5 n omtepaesae eodpae.The phases. second plate-shaped the form and 3 3 þ n ugse httepeec fthe of presence the that suggested and e tal et Lee 2 noprt noteBa the into incorporate þ . t,wihi eo h ouiiyof solubility the below is which at%, 0.4 atc ie omn oo ainin cation donor a forming sites lattice 3 8 bevda nemdaelayer intermediate an observed [8] . þ cuidteBa the occupied 3 3 enhl,Chiang Meanwhile, . ceramics 6 3 Ti þ 17 tteganboundary grain the at 2 3 O þ 2 grains. 40 þ atc ie,while sites, lattice 2 3 þ ultiei the in sublattice aeswl grow will layers þ tlwdopant low at ie hnlow when sites )i slightly is Y) tal et 5457 . Downloaded By: [Du, K.] At: 00:06 31 October 2007 1]SY hi ...Kn,SY Chung, Mater. S.Y. Acta Kang, Soc. Kang, S.J.L. Ceram. S.J.L. Choi, Am. and S.Y. J. Yoon [14] Yoon, D.Y. D.Y. Choi, and S.Y. Kang [13] S.J.L. Ikuhara, Cho, Y. Y.K. Yamamoto, [12] T. Ikuhara, Hayashi, Y. K. Hayashi, [11] K. Yamamoto, T. [10] 2]V rsvc .Doei n .Klr .A.Crm Soc. Ceram. Am. J. Kolar, D. Soc. and Ceram. Drofenik Am. M. J. Krasevec, Soc. Drofenik, V. Ceram. M. [22] Am. and J. Makovec Kolar, D. D. [21] and Kovalenko, Makovec L. D. V’Yunov, [20] Mater. O. Acta Belous, Soc. Lu, A. Ceram. H.Y. [19] Am. and J. Lin Payne, M.H. D.A. [18] Mater. and Acta Desu Soc. Leach, S.B. Ceram. C. [17] Eur. and J. Seaton Leach, J. C. [16] and Affleck L. [15] 5458 oae ttil-ri ucin nYdpdplcytlieBaTiO Ba polycrystalline Y-doped phase in second junctions plate-shaped, triple-grain small at show located investigations STEM and TEM Conclusions 5. References under Basic support for State China Major of support. Foundation financial the Sciences the 50601027. for Natural for No. the Funds 2002CB613503) Grant thank No. Special XHS (Grant and and China KD (XLM) of Projects Foundation 50325101 Scientist Research Young No. Outstanding National Grant the to for grateful are XLM and SJZ Acknowledgments tmcseso h {110} the on steps atomic hs ihacytlsrcuesmlrt Ba to similar structure crystal a with phase by determined was which h ergnlBaTiO between determined tetragonal was relationship orientation the an techniques, diffraction electron ð BaTiO 1 8 ..Le .SgeadM ul,At Mater. Acta Ruhle, M. Soc. and Ceram. Sigle Am. W. J. Lee, Soc. Takagi, S.B. Ceram. T. [8] Am. and J. Chiang Umeya, Y.-M. K. [7] and Wang D.Y. [6] 9 .Ymmt,Y khr,K Hayashi, K. Ikuhara, Y. Yamamoto, T. [9] 5 .Nmt n .Oa .A.Crm Soc. Ceram. Am. J. Oda, I. and Nemoto H. [5] 4 ..RsmnadN uhre,J Electroceram. J. Mukherjee, N. and Reaney, Roseman I.M. R.D. Sinclair, [4] D.C. Feteira, A. [3] 2 .Ksi .Mzn n .Caoo p.J pl Phys. Appl. J. Jpn. 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