DOCSLIB.ORG

Isotropic Pauli-Limited Superconductivity in the Infinite-Layer Nickelate Nd0.775Sr0.225Nio2

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Isotropic Pauli-Limited Superconductivity in the Infinite-Layer Nickelate Nd0.775Sr0.225Nio2 Isotropic Pauli-Limited Superconductivity in the Infinite-Layer Nickelate Nd0.775Sr0.225NiO2 Bai Yang Wang,*1,2 Danfeng Li,2,3 Berit H. Goodge,4 Kyuho Lee,1,2 Motoki Osada2,5, Shannon P. Harvey2,3, Lena F. Kourkoutis,4,6 Malcolm R. Beasley3, and Harold Y. Hwang*2,3 1Department of Physics, Stanford University, Stanford, CA 94305, United States. 2Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, United States. 3Department of Applied Physics, Stanford University, Stanford, CA 94305, United States. 4School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, United States. 5Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, United States. 6Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853, United States. *e-mail: [email protected]; [email protected]. ABstract The recent observation of superconductivity in thin film infinite-layer nickelates1–3 offers fresh terrain for investigating superconductivity in layered oxides4. A wide range of perspectives5–10, emphasizing single- or multi-orbital electronic structure, Kondo or Hund’s coupling, and analogies to cuprates, have been theoretically proposed. Clearly further experimental characterization of the superconducting state is needed to develop a foundational understanding of the nickelates. Here we use magnetotransport measurements to probe the superconducting anisotropy in Nd0.775Sr0.225NiO2. We find that the upper critical field is surprisingly isotropic at low temperatures, despite the layered crystal structure. We deduce that under magnetic field, superconductivity is strongly Pauli-limited, such that the paramagnetic effect dominates over orbital de-pairing. Underlying this isotropic response is a substantial anisotropy in the superconducting coherence length, at least four times longer in-plane than out-of-plane. A prominent low-temperature upturn in the upper critical field indicates the likelihood of an unconventional ground state. Main A key characteristic of layered superconductors is an upper critical field Hc2 often exhibiting substantial anisotropy g º Hc2,||/Hc2,^, where Hc2,|| and Hc2,^ indicate magnetic fields in the a-b plane and along the crystal c-direction, respectively. In layered oxides such as cuprates11, ruthenates12, and cobaltates13, the anisotropy reflects the two-dimensional (2D) nature of both the crystal and electronic structure. The case for the recently discovered infinite-layer nickelates is a priori interesting: although it shares the same crystal structure as infinite-layer cuprates, calculations indicate both a quasi-2D hole band and three-dimensional (3D) electron bands are present in the nickelates for a broad range of electron interactions5,6. The relative importance of these bands is a subject of much interest with respect to the superconducting state. More generally, nickelates provide a new system within which to explore longstanding debates on the role of dimensionality for superconductivity. With these motivations, we have studied the superconducting anisotropy through resistive measurements of Hc2 in thin-film Nd0.775Sr0.225NiO2. This composition has the highest crystallinity in our recent investigations, as well as a superconducting transition temperature Tc among the peak values observed across the superconducting dome2. As previously reported, our optimal samples are capped with SrTiO3, and are bounded in thickness to below ~10 nm; above this we observe mixed-phase formation or decomposition. A high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image is shown in Fig. 1a. In good agreement with prior observations, c-axis oriented crystalline coherence is observed throughout the film, together with extended defects primarily based on vertical Ruddlesden-Popper (RP) type faults. Figure 1b, c shows the temperature-dependent resistivity r(T) in the low temperature region, with varying magnetic field applied along the c-axis (H^) and the a-b plane (H||, transverse geometry). While minimal magnetoresistance is observed in the normal state, the superconducting transition is suppressed with increasing magnetic field, allowing us to extract the temperature dependence of Hc2. Figure 2 shows the main result of this study: the magnetic field-temperature phase diagram of Hc2,^ and Hc2,||, down to 0.5 K. Here Tc and Hc2 are identified as the resistive transition reaching 50% of the normal state, as discussed below. Overall, the most striking feature is that Hc2 is largely isotropic at low temperatures (as emphasized in Fig. 2a inset), despite the layered crystal 5,6 structure, the quasi-2D nature of the !"#$%# hole band and the thin film geometry. Does this reflect a rather isotropic electronic structure, and superconducting coherence length, as unusually 14 found in (K,Ba)FeAs2 (ref. )? Or does it have a different fundamental origin? Our aim is to address this central question. As we argue below, Hc2 is dominated by the isotropic spin response, rather than orbital effects, over much of the phase diagram. Such strongly Pauli-limited superconductivity in nickelates appears unique among the layered oxides. We start by examining the magnetoresistive transition observed in Fig. 1b, c. The visible broadening can have contributions from static compositional inhomogeneity, superconducting fluctuations, and vortex motion in this type-II superconductor1,9. In terms of inhomogeneity, the RP-type faults likely give rise to a spread in Tc. Regarding superconducting fluctuations, we fit the onset of superconductivity following the 2D Aslamazov-Larkin (AL) formulism15,16, with AL representative fits shown in the insets of Fig. 1b, c. From this we obtain a corresponding Tc , above which superconducting fluctuations significantly impact the resistive transition. We note that this regime also includes effects arising from static inhomogeneities. As for vorteX motion, we investigate its contribution in scaled Arrhenius plots, as shown in Fig. 3a, b. Between the normal state and the measurement noise floor, exponentially decreasing resistivity is seen for both orientations across several orders of magnitude. This is well described 17 by thermally-activated vorteX motion : r(T,H) = r0(H) exp(U0/kBT) where r0 is the resistivity prefactor, U0 is the activation energy and kB is Boltzmann’s constant. Figure 3c shows U0 17,18 extracted using this form. Similar to cuprates , U0 for H^ and H|| exhibits regions of power- law dependence on magnetic field. Note that the success of this fitting implies that vortex motion is relevant for H||, and the large difference in U0 values between H^ and H|| indicates substantial VM vorteX-motion anisotropy. We define Tc as the temperature above which resistivity deviates VM from thermally-activated behavior, and attribute the resistive transition below Tc predominantly to vortex motion. Summarizing the onset of fluctuations and vortex motion, we construct the phase diagrams in Fig. VM AL 4a, b. In addition to Hc (T) and Hc (T), we plot representative candidate proxies for Hc2: 90% 50% 1% Hc (T), Hc (T) and Hc (T), corresponding to the resistivity reaching 90%, 50%, and 1% of VM AL the normal state. Between Hc (T) and Hc (T) (extrapolating to 27% and 80% of the resistive transition for H = 0 T) there is a regime where the magnetoresistance can serve as a reliable indicator of Hc2, free from vorteX creep or superconducting fluctuations which tend to 19 50% under/over-estimate Hc2, as well as distort its functional form . Hence, we use Hc to measure Hc2; our conclusions are robust to variations within this regime aside from specific numerical values. We next focus on magnetotransport near Tc, taking advantage of the simplification in the critical regime arising from diverging length scales. Here the central observation is a T-linear 1/2 dependence of Hc2,^ and a T dependence of Hc2,|| (Fig. 4c). We first consider purely orbital de- pairing (superconductivity suppressed by the energy cost of the field-induced supercurrent), with 1/2 the characteristic T dependence of Hc2,|| arising from 2D confinement. This is commonly observed for superconductors thinner than the Ginzburg-Landau (GL) coherence length20,21, and is a reasonable possibility here, given the thickness limits for stabilizing Nd0.775Sr0.225NiO2. In 22 such geometries, Hc2 is well described by the linearized GL form (generalized to an anisotropic, c-axis thickness-limited superconductor) as 01 - &'(,* (-) = ( 81 − ;, (1) 23456(0) -' > √1201 - ( &'(,∥(-) = 81 − ; , (2) 23456(0)! -' where f0 is the flux quantum, xab(0) is the in-plane zero-temperature coherence length, and d is the superconducting thickness. Using these forms, we extract xab(0) = 42.6 ± 0.1 Å and d = 225 ± 7 Å. In previous studies on other material systems, d derived from such analysis was in good quantitative agreement with the physical thickness of the film20,23, except for cases with dominant spin-orbit scattering24,25, for which the thickness is underestimated. Here we deduce a thickness that is 2.3 – 3 times larger than the observed thickness of the film (Table S1, Supplementary Information), which we take to be an unphysical discrepancy. Furthermore, this analysis presumes confinement preventing vortex entry for H||, inconsistent with evident vortex motion in this orientation (Fig. 3c). Finally, 2D confinement of an orbital-limited superconductor usually leads to a dramatic enhancement of Hc2,|| over Hc2,^ that
Load more

Recommended publications
  • Determination of Supercooling Degree, Nucleation and Growth Rates, and Particle Size for Ice Slurry Crystallization in Vacuum
    crystals Article Determination of Supercooling Degree, Nucleation and Growth Rates, and Particle Size for Ice Slurry Crystallization in Vacuum Xi Liu, Kunyu Zhuang, Shi Lin, Zheng Zhang and Xuelai Li * School of Chemical Engineering, Fuzhou University, Fuzhou 350116, China; [email protected] (X.L.); [email protected] (K.Z.); [email protected] (S.L.); [email protected] (Z.Z.) * Correspondence: [email protected] Academic Editors: Helmut Cölfen and Mei Pan Received: 7 April 2017; Accepted: 29 April 2017; Published: 5 May 2017 Abstract: Understanding the crystallization behavior of ice slurry under vacuum condition is important to the wide application of the vacuum method. In this study, we first measured the supercooling degree of the initiation of ice slurry formation under different stirring rates, cooling rates and ethylene glycol concentrations. Results indicate that the supercooling crystallization pressure difference increases with increasing cooling rate, while it decreases with increasing ethylene glycol concentration. The stirring rate has little influence on supercooling crystallization pressure difference. Second, the crystallization kinetics of ice crystals was conducted through batch cooling crystallization experiments based on the population balance equation. The equations of nucleation rate and growth rate were established in terms of power law kinetic expressions. Meanwhile, the influences of suspension density, stirring rate and supercooling degree on the process of nucleation and growth were studied. Third, the morphology of ice crystals in ice slurry was obtained using a microscopic observation system. It is found that the effect of stirring rate on ice crystal size is very small and the addition of ethylene glycoleffectively inhibits the growth of ice crystals.
    [Show full text]
  • A Supercooled Magnetic Liquid State in the Frustrated Pyrochlore Dy2ti2o7
    A SUPERCOOLED MAGNETIC LIQUID STATE IN THE FRUSTRATED PYROCHLORE DY2TI2O7 A Dissertation Presented to the Faculty of the Graduate School of Cornell University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy by Ethan Robert Kassner May 2015 c 2015 Ethan Robert Kassner ALL RIGHTS RESERVED A SUPERCOOLED MAGNETIC LIQUID STATE IN THE FRUSTRATED PYROCHLORE DY2TI2O7 Ethan Robert Kassner, Ph.D. Cornell University 2015 A “supercooled” liquid forms when a liquid is cooled below its ordering tem- perature while avoiding a phase transition to a global ordered ground state. Upon further cooling its microscopic relaxation times diverge rapidly, and eventually the system becomes a glass that is non-ergodic on experimental timescales. Supercooled liquids exhibit a common set of characteristic phenom- ena: there is a broad peak in the specific heat below the ordering temperature; the complex dielectric function has a Kohlrausch-Williams-Watts (KWW) form in the time domain and a Havriliak-Negami (HN) form in the frequency do- main; and the characteristic microscopic relaxation times diverge rapidly on a Vogel-Tamman-Fulcher (VTF) trajectory as the liquid approaches the glass tran- sition. The magnetic pyrochlore Dy2Ti2O7 has attracted substantial recent attention as a potential host of deconfined magnetic Coulombic quasiparticles known as “monopoles”. To study the dynamics of this material we introduce a high- precision, boundary-free experiment in which we study the time-domain and frequency-domain dynamics of toroidal Dy2Ti2O7 samples. We show that the EMF resulting from internal field variations can be used to robustly test the predictions of different parametrizations of magnetization transport, and we find that HN relaxation without monopole transport provides a self-consistent de- scription of our AC measurements.
    [Show full text]
  • A Review of Liquid-Glass Transitions
    A Review of Liquid-Glass Transitions Anne C. Hanna∗ December 14, 2006 Abstract Supercooling of almost any liquid can induce a transition to an amorphous solid phase. This does not appear to be a phase transition in the usual sense — it does not involved sharp discontinuities in any system parameters and does not occur at a well-defined temperature — instead, it is due to a rapid increase in the relaxation time of the material, which prevents it from reaching equilibrium on timescales accessible to experimentation. I will examine various models of this transition, including elastic, mode-coupling, and frustration-based explanations, and discuss some of the problems and apparent paradoxes found in these models. ∗University of Illinois at Urbana-Champaign, Department of Physics, email: [email protected] 1 Introduction While silicate glasses have been a part of human technology for millenia, it has only been known since the 1920s that any supercooled liquid can in fact be caused to enter an amor- phous solid “glass” phase by further reduction of its temperature. In addition to silicates, materials ranging from metallic alloys to organic liquids and salt solutions, and having widely varying types of intramolecular interactions, can also be good glass-formers. Also, the glass transition can be characterized in terms of a small dimensionless parameter which is different on either side of the transition: γ = Dρ/η, where D is the molecular diffusion constant, ρ is the liquid density, and η is the viscosity. This all seems to suggest that there may be some universal aspect to the glass transition which does not depend on the specific microscopic properties of the material in question, and a significant amount of research has been done to determine what an appropriate universal model might be.
    [Show full text]
  • Surface and Bulk Crystallization of Glass-Ceramic in the Na2o–Cao
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Digital.CSIC M Romero, J.Ma Rincón. Surface and Bulk Crystallization of Glass-Ceramic in the Na2O-CaO-ZnO- PbO-Fe2O3-Al2O3-SiO2 System Derived from a Goethite Waste Journal of the American Ceramic Society, 82 (1999) [5], 1313-1317 DOI: 10.1111/j.1151-2916.1999.tb01913.x Surface and Bulk Crystallization of Glass-Ceramic in the Na2O–CaO–ZnO–PbO–Fe2O3–Al2O3–SiO2 System Derived from a Goethite Waste Maximina Romero* and Jesús María Rincón Instituto E. Torroja de Ciencias de la Construccion (The Glass-Ceramics Laboratory), CSIC, 28033 Madrid, Spain Abstract A goethite waste from zinc hydrometallurgical processes has been used to produce a glass- ceramic in the Na2O–CaO–ZnO–PbO–Fe2O3–Al2O3–SiO2 system. The surface and bulk microstructure of this glass-ceramic have been studied by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The surface was comprised of crystalline and glassy areas. Two different types of crystalline growth and two morphologies were observed in the crystallized and glassy zones, respectively. The bulk microstructure was composed of a homogeneously distributed dendritic network comprised of small crystallites of magnetite. A glassy matrix was observed surrounding the magnetite network. Further heat treatment produced the precipitation of a non-stoechiometric zinc ferrite with magnetite crystals, being the nucleating agents of the secondary phase. I. Introduction Glass-ceramics prepared by controlled crystallization of glasses have become established in a wide range of technical and technological applications.1 In the “classical method” usually applied to produce glass-ceramics, an appropriate mixture of raw materials is melted and poured into a mold to produce a glass.
    [Show full text]
  • A Topographic View of Supercooled Liquids and Glass Formation Author(S): Frank H
    A Topographic View of Supercooled Liquids and Glass Formation Author(s): Frank H. Stillinger Source: Science, New Series, Vol. 267, No. 5206 (Mar. 31, 1995), pp. 1935-1939 Published by: American Association for the Advancement of Science Stable URL: http://www.jstor.org/stable/2886441 Accessed: 31/03/2010 22:44 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=aaas. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. American Association for the Advancement of Science is collaborating with JSTOR to digitize, preserve and extend access to Science. http://www.jstor.org FRONTIERS IN MATERIALS SCIENCE: ARTICLES Hall and P.
    [Show full text]
  • Supercooling and Nucleation
    Supercooling and Nucleation What is the stabilizing liquid water when T < 0oC ? Supersaturation and Nucleation What is stabilizing supersaturated sodium acetate in water ? Lecture 5 Supercooling and Nucleation Phase transition is the process that changes the states of matter. In reality, phase transition is more than the simply thermodynamic picture we learned from undergraduate physical chem- istry, which involved both heat and mass transfer at the interfaces between two or more phases. We are able to explain several important physical phenomena by applying our knowledge of fluid mechanics in Lecture 4 to phase transition. On example is the supercooling of liquid, that crystallization does not occur even if temperature is lower than the freezing point, due to the absence of nucleation. In this lecture we will study the phenomenon of nucleation during freezing, a process that nano- to microscale crystals called nuclei forms in the liquid phase. Nucleation is the first step of crystallization and also a kinetic process. Even when crystal- lization is thermodynamically favorable, nucleation can be slow or even unobservable under supercooling. What is the cause of supercooling? Can we engineer the nucleation process? We will find the answers in this lecture. 5.1 Thermodynamics of freezing For a pure liquid with melting temperature Tm, the Gibbs free energy between its solid state (S) and liquid state (L) has the relation: • T>T G <G Liquid is thermodynamically favored m ! L S ! • T<T G >G Solid is thermodynamically favored m ! L S ! The change of free energy G as a function of temperature T of a solid-liquid phase transition can be seen in Figure 5.1.
    [Show full text]
  • The Contribution of Constitutional Supercooling to Nucleation and Grain Formation
    The Contribution of Constitutional Supercooling to Nucleation and Grain Formation D.H. StJohn1a, A. Prasad1b, M.A. Easton2c and M. Qian2d 1 Centre for Advanced Materials Processing and Manufacturing (AMPAM), School of Mechanical and Mining Engineering, The University of Queensland, St Lucia, QLD, Australia, 4072 2 RMIT University, School of Aerospace, Mechanical and Manufacturing Engineering, GPO Box 2476, Melbourne, VIC 3001, Australia [email protected], [email protected], [email protected] [email protected], Abstract The concept of constitutional supercooling (CS) including the term itself was first described and discussed qualitatively by Rutter and Chalmers (1953) in order to understand the formation of cellular structures during the solidification of tin, and then quantified by Tiller, Jackson, Rutter, and Chalmers (1953). On that basis, Winegard and Chalmers (1954) further considered ‘supercooling and dendritic freezing of alloys’ where they described how CS promotes the heterogeneous nucleation of new crystals and the formation of an equiaxed zone. Since then the importance of CS in promoting the formation of equiaxed microstructures in both grain refined and unrefined alloys has been clearly revealed and quantified. This paper describes our current understanding of the role of CS in promoting nucleation and grain formation. It also highlights that CS, on the one hand, develops a nucleation-free zone surrounding each nucleated and growing grain and, on the other hand, protects this grain from readily remelting when temperature fluctuations occur due to convection. Further, due to the importance of the diffusion field that generates CS recent analytical models are evaluated and compared with a numerical model.
    [Show full text]
  • Criterion for Constitutional Supercooling at Solid-Liquid Interface in Initial Transient Solidification with Varying Solute Content at Interface
    Materials Transactions, Vol. 52, No. 2 (2011) pp. 179 to 188 #2011 The Japan Institute of Metals Criterion for Constitutional Supercooling at Solid-Liquid Interface in Initial Transient Solidification with Varying Solute Content at Interface Hiroshi Kato and Yukihiko Ando* Division of Mechanical Science and Engineering, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan A criterion for appearance of the constitutional supercooling at the solid-liquid interface in the initial transient solidification is discussed theoretically and experimentally. First, a relation between the moving velocity of the interface and the solute content was analyzed to derive a moving velocity of the interface under a simple model of the linear change in the solute content at the interface. And, a criterion for appearance of the constitutional supercooling at the planar interface was analyzed to obtain the distance of the stable growth of the interface with the planar shape. Then, the solidification experiment was carried out with the Al-4 mass% Cu alloy: the aluminum alloy was inserted in the alumina tube of 0.4 to 2 mm in inner diameter and heated for 2:54 h under a temperature gradient to obtain the stationary interface, and then the alumina tube was cooled in the furnace for 0 to 45 s. After furnace cooling, the alumina tube was quenched in water to observe the interface. The interface with the planar shape appeared for 2030 s after the start of furnace cooling, and then the columnar structure grew ahead of the interface. Then the solute content in the solid behind the interface was analyzed to show that the solute content in the specimen quenched after furnace cooling was different from that in the specimen quenched without furnace cooling.
    [Show full text]
  • Deep Supercooling, Vitrification and Limited Survival to –100°C in the Alaskan Beetle Cucujus Clavipes Puniceus (Coleoptera: Cucujidae) Larvae
    502 The Journal of Experimental Biology 213, 502-509 Published by The Company of Biologists 2010 doi:10.1242/jeb.035758 Deep supercooling, vitrification and limited survival to –100°C in the Alaskan beetle Cucujus clavipes puniceus (Coleoptera: Cucujidae) larvae T. Sformo1,*, K. Walters2, K. Jeannet1, B. Wowk3, G. M. Fahy3, B. M. Barnes1 and J. G. Duman2 1Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA, 2Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA and 321st Century Medicine, Inc., Fontana, CA, USA *Author for correspondence at present address: PO Box 69 Department of Wildlife Management, North Slope Borough Barrow, AK 99723, USA ([email protected]) Accepted 3 November 2009 SUMMARY Larvae of the freeze-avoiding beetle Cucujus clavipes puniceus (Coleoptera: Cucujidae) in Alaska have mean supercooling points in winter of –35 to –42°C, with the lowest supercooling point recorded for an individual of –58°C. We previously noted that some larvae did not freeze when cooled to –80°C, and we speculated that these larvae vitrified. Here we present evidence through differential scanning calorimetry that C. c. puniceus larvae transition into a glass-like state at temperatures <–58°C and can avoid freezing to at least –150°C. This novel finding adds vitrification to the list of insect overwintering strategies. While overwintering beneath the bark of fallen trees, C. c. puniceus larvae may experience low ambient temperatures of around –40°C (and lower) when microhabitat is un-insulated because of low snow cover. Decreasing temperatures in winter are correlated with loss of body water from summer high levels near 2.0 to winter lows near 0.4mgmg–1drymass and concomitant increases in glycerol concentrations (4–6moll–1) and thermal hysteresis.
    [Show full text]
  • Chem Soc Rev 1
    1 Chem Soc Rev 1 5 TUTORIAL REVIEW 5 Crystallisation in oxide glasses – a tutorial review Q1 Q2 10 a a b 10 Cite this: DOI: 10.1039/c3cs60305a N. Karpukhina,* R. G. Hill and R. V. Law Glasses and glass-ceramics have had a tremendous impact upon society and continue to have profound industrial, commercial and domestic importance. A remarkable number of materials, with exceptional 15 optical and mechanical properties, have been developed and enhanced using the glass-ceramic method 15 over many years. In order to develop glass-ceramics, glass is initially prepared via high temperature synthesis and subsequently heat treated, following a carefully designed and controlled process. A glass- ceramic system comprises crystalline and non-crystalline phases; in multicomponent systems these phases are significantly different from the initial glass composition. The properties of glass-ceramics are 20 defined by microstructure, crystal morphology as well as the final chemical composition and physical 20 properties of the residual glass. Knowing the mechanism of glass crystallisation, it is possible to predict and design a glass-ceramic system with near-ideal properties that exactly fulfil the requirements for a Received 18th August 2013 particular application. This tutorial review is a basic introduction to the crystallisation in glasses and DOI: 10.1039/c3cs60305a mainly focuses on silicate and closely related oxide glasses. The review describes and discusses key 25 learning points in five different sections, which facilitate the understanding of glass crystallisation and 25 www.rsc.org/csr development of glass-ceramics. Key learning points 30 (1) Nucleation and crystal growth are two fundamental stages of crystallisation in glass.
    [Show full text]
  • Supercooling Slushies
    How to Create SUPERCOOLING SLUSHIES YOU WILL NEED C R E A T E D B Y A A S H I K A S U L A B E L L E access to a freezer • 2 plastic bottles of pop (any size) • 1 metal or glass container (optional) • timer or clock THE EXPERIMENT Step 1: Place your first pop bottle in the freezer for about 2.5 - 4 hours. Make sure to keep track of how long it takes for your pop to freeze completely. This may require you to check in periodically on your pop bottle. Do not use glass bottles or aluminum cans, as they may shatter or explode in the freezer! Step 2: Once you know how long it takes for your pop to freeze fully, subtract 15 minutes from the time it takes to freeze your pop fully. This calculated time will approximately be how long it takes to supercool your pop. Example: 3 hours to freeze a pop means supercooling time is about 2 hours and 45 minutes. WARNING: Do not drink your supercooled liquid when it comes out of the freezer, as the liquid might expand between your teeth and injure you. Wait until it is in slush form before drinking (see next steps). Step 3: Now that you have your calculated supercooling time, shake up your second pop bottle and place in the freezer for that amount of calculated time. You will not need your first bottle anymore. Supercooling may take a few attempts to get right. Step 4: Method 1: Once your second pop bottle is done supercooling (not completely frozen!), take it out of the freezer.
    [Show full text]
  • Is Ice Nucleation from Supercooled Water Insensitive to Surface Roughness? † ‡ † James M
    Article pubs.acs.org/JPCC Is Ice Nucleation from Supercooled Water Insensitive to Surface Roughness? † ‡ † James M. Campbell, Fiona C. Meldrum, and Hugo K. Christenson*, † ‡ School of Physics and Astronomy and School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K. *S Supporting Information ABSTRACT: There is much evidence that nucleation of liquid droplets from vapor as well as nucleation of crystals from both solution and vapor occurs preferentially in surface defects such as pits and grooves. In the case of nucleation of solid from liquid (freezing) the situation is much less clear-cut. We have therefore carried out a study of the freezing of 50 μm diameter water drops on silicon, glass, and mica substrates and made quantitative comparisons for smooth substrates and those roughened by scratching with three diamond powders of different size distributions. In all cases, freezing occurred close to the expected homogeneous freezing temperature, and the nucleation rates were within the range of literature data. Surface roughening had no experimentally significant effect on any of the substrates studied. In particular, surface roughening of micawhich has been shown to cause dramatic differences in crystal nucleation from organic vaporshas an insignificant effect on ice nucleation from supercooled water. The results also show that glass, silicon, and mica have at best only a marginal ice-nucleating capability which does not differ appreciably between the substrates. The lack of effect of roughness on freezing can be rationalized in terms of the relative magnitudes of interfacial free energies and the lack of a viable two-step mechanism, which allows vapor nucleation to proceed via a liquid intermediate.
    [Show full text]