{"title":"Tin titanate—the hunt for a new ferroelectric perovskite","authors":"J. Gardner, Atul Thakre, Ashok Kumar, J. Scott","doi":"10.1088/1361-6633/ab37d4","DOIUrl":null,"url":null,"abstract":"We review all the published literature and show that there is no experimental evidence for homogeneous tin titanate SnTiO3 in bulk or thin-film form. Instead a combination of unrelated artefacts are easily misinterpreted. The x-ray Bragg data are contaminated by double scattering from the Si substrate, giving a strong line at the 2θ angle exactly where perovskite SnTiO3 should appear. The strong dielectric divergence near 560 K is irreversible and arises from oxygen site detrapping, accompanied by Warburg/Randles interfacial anomalies. The small (4 µC cm−2) apparent ferroelectric hysteresis remains in samples shown to be pure (Sn,Ti)O2 rutile/cassiterite, in which ferroelectricity is forbidden. Only very recent work reveals real bulk SnTiO3, but it possesses an ilmenite-like structure with an elaborate array of stacking faults, not suitable for ferroelectric devices. Unpublished TEM data reveal an inhomogeneous SnO layered structured thin films, related to shell–core structures. The harsh conclusion is that there is a combination of unrelated artefacts masquerading as ferroelectricity in powders and ALD films; and only a trace of a second phase in PLD film data suggests any perovskite content at all. The fact that x-ray, dielectric, and hysteresis data all lead to the wrong conclusion is instructive and reminds us of earlier work on copper calcium titanate (a well-known boundary-layer capacitor).","PeriodicalId":21110,"journal":{"name":"Reports on Progress in Physics","volume":"55 1","pages":""},"PeriodicalIF":19.0000,"publicationDate":"2019-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"11","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Reports on Progress in Physics","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1088/1361-6633/ab37d4","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 11
Abstract
We review all the published literature and show that there is no experimental evidence for homogeneous tin titanate SnTiO3 in bulk or thin-film form. Instead a combination of unrelated artefacts are easily misinterpreted. The x-ray Bragg data are contaminated by double scattering from the Si substrate, giving a strong line at the 2θ angle exactly where perovskite SnTiO3 should appear. The strong dielectric divergence near 560 K is irreversible and arises from oxygen site detrapping, accompanied by Warburg/Randles interfacial anomalies. The small (4 µC cm−2) apparent ferroelectric hysteresis remains in samples shown to be pure (Sn,Ti)O2 rutile/cassiterite, in which ferroelectricity is forbidden. Only very recent work reveals real bulk SnTiO3, but it possesses an ilmenite-like structure with an elaborate array of stacking faults, not suitable for ferroelectric devices. Unpublished TEM data reveal an inhomogeneous SnO layered structured thin films, related to shell–core structures. The harsh conclusion is that there is a combination of unrelated artefacts masquerading as ferroelectricity in powders and ALD films; and only a trace of a second phase in PLD film data suggests any perovskite content at all. The fact that x-ray, dielectric, and hysteresis data all lead to the wrong conclusion is instructive and reminds us of earlier work on copper calcium titanate (a well-known boundary-layer capacitor).
期刊介绍:
Reports on Progress in Physics is a highly selective journal with a mission to publish ground-breaking new research and authoritative invited reviews of the highest quality and significance across all areas of physics and related areas. Articles must be essential reading for specialists, and likely to be of broader multidisciplinary interest with the expectation for long-term scientific impact and influence on the current state and/or future direction of a field.