Materials Science and Engineering R 68 (2010) 89–133 Contents lists available at ScienceDirect Materials Science and Engineering R journal homepage: www.elsevier.com/locate/mser Advances in the growth and characterization of magnetic, ferroelectric, and multiferroic oxide thin films L.W. Martin a,b,*, Y.-H. Chu c, R. Ramesh d,e,f a Department of Materials Science and Engineering, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA b Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA c Department of Materials Science and Engineering, National Chiao Tung University, HsinChu 30100, Taiwan d Department of Materials Science and Engineering University of California, Berkeley, Berkeley, CA 94720, USA e Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA f Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA ARTICLE INFO ABSTRACT Article history: The growth and characterization of functional oxide thin films that are ferroelectric, magnetic, or both at Received 22 March 2010 the same time are reviewed. The evolution of synthesis techniques and how advances in in situ Accepted 24 March 2010 characterization have enabled significant acceleration in improvements to these materials are described. Available online 21 April 2010 Methods for enhancing the properties of functional materials or creating entirely new functionality at interfaces are covered, including strain engineering and layering control at the atomic-layer level. Keywords: Emerging applications of these functional oxides such as achieving electrical control of ferromagnetism Thin films and the future of these complex functional oxides is discussed. Multiferroic ß 2010 Elsevier B.V. All rights reserved. Magnetic ferroelectric Complex oxides Contents 1. Introduction . 90 2. The wide-world of complex oxides: structures and chemistry . 90 3. Advances in the growth of oxide thin films . 92 3.1. Thin film growth modes and epitaxy. 92 3.2. Pulsed-laser ablation-based techniques. 94 3.2.1. Laser-material interactions . 95 3.2.2. Recent advances in pulsed laser deposition . 96 3.3. Molecular beam epitaxy . 97 3.4. Sputtering . 97 3.5. Metal-organic chemical vapor deposition . 97 3.6. Solution-based thin film deposition techniques . 97 3.7. Low-temperature aqueous solution depositions . 98 Abbreviations: AAO, anodized aluminum oxide; AF, antiferromagnet; AFM, atomic force microscopy; BFO, BiFeO3; BMO, BiMnO3; BTO, BaTiO3; c-AFM, conducting atomic force microscopy; CBD, chemical bath deposition; CFO, CoFe2O4; CMR, colossal magnetoresistance; CSD, chemical solution deposition; DSO, DyScO3; EB, exchange bias; ED, electroless deposition; eV, electron volt; FeRAM, ferroelectric random access memory; FM, ferromagnet; GMR, giant magnetoresistance; GSO, GdScO3; H, magnetic field; HRTEM, high-resolution transmission electron microscopy; LSMO, La0.7Ca0.3MnO3; LPD, liquid phase deposition; LSAT, (LaAlO3)0.29–(Sr0.5Al0.5TaO3)0.71; MBE, molecular beam epitaxy; MOCVD, metal-organic chemical vapor deposition; MRAM, magnetic random access memory; Oe, Oersted; PS, saturation polarization; P–E, polarization–electric field; PCD, photochemical deposition; PEEM, photoemission electron microscopy; PFM, piezoresponse force microscopy; PLD, pulsed laser deposition; PMN-PT, Pb(Mg0.33Nb0.67)O3–PbTiO3; PTO, PbTiO3; PZT, Pb(Zrx,Ti1Àx)O3; RF, radio-frequency; RHEED, reflection high-energy electron diffraction; RHEED-TRAXS, reflection high- energy electron diffraction total reflection angle X-ray spectroscopy; SBT, SrBi2Ta2O9; SPES, spin-resolved photoemission spectroscopy; SQUID, superconducting quantum interference device; SRO, SrRuO3; STO, SrTiO3; TC, Curie temperature; TN, Neel temperature; TEM, transmission electron microscopy; TMR, tunnel magnetoresistance; ToF- ISARS, time-of-flight ion scattering and recoil spectroscopy; XMCD, X-ray magnetic circular dichroism; YMO, YMnO3. * Corresponding author at: Department of Materials Science and Engineering, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA. Tel.: +1 217 244 9162; fax: +1 217 333 2736. E-mail address: [email protected] (L.W. Martin). 0927-796X/$ – see front matter ß 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.mser.2010.03.001 90 L.W. Martin et al. / Materials Science and Engineering R 68 (2010) 89–133 4. Ferroelectricity in oxides . 98 4.1. Definition of ferroelectric materials . 98 4.2. Brief history of ferroelectrics . 98 4.3. Thin film ferroelectric phenomena. 99 4.3.1. Size effects in ferroelectrics . 99 4.3.2. Strain effects in ferroelectricity. 100 4.3.3. Artificially engineered ferroelectrics. 102 4.3.4. Controlling ferroelectric domain structures . 103 4.4. Ferroelectric devices and integration . 105 4.5. Ferroelectric tunnel junctions and novel transport phenomena. 106 5. Magnetism in oxides . 106 5.1. Definition of magnetic materials . 106 5.2. Brief history of magnetic oxides . 107 5.3. Common types of magnetism in transition metal oxides . 107 5.3.1. Superexchange. 107 5.3.2. Double exchange . 108 5.3.3. RKKY coupling . 108 5.4. Modern magnetic oxides . 108 5.4.1. Ferrites . 108 5.4.2. Manganites . 109 5.5. Thin film magnetic phenomena . 110 5.5.1. Superlattice effects . 110 5.5.2. Exchange coupling across interfaces. 111 6. Multiferroism and magnetoelectricity . 112 6.1. Scarcity of multiferroics . 112 6.2..