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dc.contributor.authorHowieson, Grant W.
dc.contributor.authorMishra, Karuna K.
dc.contributor.authorGibbs, Alexandra S.
dc.contributor.authorKatiyar, Ram S.
dc.contributor.authorScott, James F.
dc.contributor.authorMorrison, Finlay D.
dc.contributor.authorCarpenter, Michael
dc.identifier.citationHowieson , G W , Mishra , K K , Gibbs , A S , Katiyar , R S , Scott , J F , Morrison , F D & Carpenter , M 2021 , ' Structural phase transitions in the geometric ferroelectric LaTa O 4 ' , Physical Review. B, Condensed matter and materials physics , vol. 103 , no. 1 , 014119 .
dc.identifier.otherPURE: 272844850
dc.identifier.otherPURE UUID: 4ef5b6c6-7ce3-496c-9e8c-7190fda6cd25
dc.identifier.otherScopus: 85100318721
dc.identifier.otherORCID: /0000-0002-2813-3142/work/88730808
dc.identifier.otherORCID: /0000-0002-7012-1831/work/88730979
dc.identifier.otherWOS: 000613140600002
dc.descriptionFunding: School of Chemistry, University of St Andrews for funding of a studentship to GWH through the EPSRC doctoral training grant (Grant No. EP/N509759/1). This work was also facilitated by funding provided by the EPSRC (Grant No. EP/P024637/1). K.K.M. and R.S.K. acknowledge financial support from the Department of Defense, USA (DoD Grant No. FA9550-20-1-0064). The RUS component of this work was funded by EPSRC Grant No. EP/P024904/1.en
dc.description.abstractThe recent report of an intermediate incommensurately modulated orthorhombic phase in LaTaO4 has prompted a re-examination of the phase transition sequence in LaTaO4 as a function of temperature. With falling temperature, the sequence of phases examined is (orthorhombic) Cmc21(C)↔Cmc21(IC)↔(monoclinic)P21/c, with C and IC denoting commensurate and incommensurate phases, respectively. The orthorhombic to monoclinic transition, Tm-o, is a first order reconstructive transition occurring at 440 K and TIC-C is a first-order displacive transition occurring at 500-530 K. Strain and elasticity data confirm a first-order transition between the basic and modulated Cmc21 phases, with similarities to the isostructural fluoride BaMnF4. A Raman spectroscopic study of the LaTaO4 phase transition indicates that the IC-C phase transition is driven by a soft zone-boundary phonon (unstable) of the commensurate orthorhombic (Cmc21) phase. The soft phonon is found to appear (underdamped) above 443 K and vanishes (overdamped) around 528 K. A large supercell of the monoclinic phase below Tm-o is proposed based on the Raman spectroscopic results.
dc.relation.ispartofPhysical Review. B, Condensed matter and materials physicsen
dc.rightsCopyright © 2021 American Physical Society. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the final published version of the work, which was originally published at
dc.subjectQC Physicsen
dc.subjectQD Chemistryen
dc.subjectTK Electrical engineering. Electronics Nuclear engineeringen
dc.subjectElectronic, Optical and Magnetic Materialsen
dc.subjectCondensed Matter Physicsen
dc.titleStructural phase transitions in the geometric ferroelectric LaTa O4en
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews.School of Chemistryen
dc.contributor.institutionUniversity of St Andrews.Centre for Designer Quantum Materialsen
dc.contributor.institutionUniversity of St Andrews.EaSTCHEMen
dc.description.statusPeer revieweden

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