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Colossal Magnetoresistance in Cuprates?

铜氧化物中的巨大磁阻？

基本信息

批准号：
EP/F035225/1
负责人：
Abbie Mclaughlin
金额：
$ 31.27万
依托单位：
University of Aberdeen
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FF035225%2F1
关键词：
Colossal Magnetoresistance Cuprates

项目摘要

In recent years there has been much research into layered cuprates due to the observation of high temperature superconductivity in such materials. Unlike normal conductors a superconductor exhibits zero electrical resistance below a critical temperature Tc and technological applications include superconducting magnets for MRI scanners, beam steering magnets in high-energy accelerators such as CERN and magnetic levitation trains. At present the record temperature at which superconductivity is observed stands at -113 degrees C in the cuprate material HgBa2Ca2Cu3O8+y. Another phenomena that has been much studied is that of negative magnetoresistance observed in perovskite manganites and Sr2FeMoO6. A negative magnetoresistant material exhibits a reduction in electronic resistivity upon application of a magnetic field and current applications of such compounds include memory storage devices. We have recently made the surprising discovery of large negative magnetoresistance in the ruthenocuprate material RuSr2Nd2-x-yCexYyCu2O10 between x = 0.7 - 0.95; -MR of up to 49% have been observed at 4 K in a 7 tesla field which is comparable to spin-polarised conductors such as CMR manganese oxide perovskites and Sr2FeMoO6 (at higher temperatures). Superconductivity is also observed in this material for x = 0.6 (Tc ~ 40 K).This is the first time that large bulk negative magnetoresistance has been observed in a cuprate material which also exhibits superconductivity at higher copper oxidation states. To investigate this phenomenon further we propose to synthesise and study the magnetotransport properties of new magnetocuprates such as 1222 MSr2R0.9Y0.2Ce0.9Cu2O10-d and 1212 MSr2RCu2O7+d (M = Co, Fe, Os, Mn, Cr, Mo, Ir, Cu; R = Nd, Pr) and cuprate spinels Cu1+xM2-xO4 (M = Mn, Cr, Fe, Ni, x = 0 / 0.2) in order to determine the possibility of observing -MR in other cuprates and to optimise the magnetoresistive properties of the cuprates. This work will not only be of great fundamental importance but may also have practical applications if it is possible to observe large negative magnetoresistance at higher temperatures

近年来，由于在层状铜氧化物材料中观察到高温超导性，人们对这类材料进行了大量的研究。与正常导体不同，超导体在临界温度Tc以下表现出零电阻，技术应用包括MRI扫描仪的超导磁体，高能加速器（如CERN和磁悬浮列车）中的光束转向磁体。目前，在铜酸盐材料HgBa 2Ca 2Cu 3 O 8 +y中观察到超导性的最高温度为-113 ℃。另一个已经被大量研究的现象是在钙钛矿锰氧化物和Sr 2FeMoO 6中观察到的负磁阻。负磁阻材料在施加磁场时表现出电子电阻率的降低，并且这种化合物的当前应用包括存储器存储器件。我们最近在x = 0.7 - 0.95之间的六方铜酸盐材料RuSr 2Nd 2-x-yCexYyCu 2 O 10中令人惊讶地发现了大的负磁阻;在4K下在7特斯拉的磁场中观察到高达49%的MR，这与自旋极化导体如CMR氧化锰钙钛矿和Sr 2FeMoO 6（在更高的温度下）相当。在x = 0.6（Tc ~ 40 K）的条件下，该材料也具有超导性，这是首次在铜氧化物材料中观察到大的体相负磁电阻，该材料在较高的铜氧化态下也具有超导性。为了进一步研究这一现象，我们提出合成和研究新的磁铜酸盐，如1222 MSr2R0.9Y0.2Ce0.9Cu2O10-d和1212 MSr 2 RCu 2 O 7 +d的磁输运性质（M = Co，Fe，Os，Mn，Cr，Mo，Ir，Cu; R = Nd，Pr）和铜酸盐尖晶石Cu_（1 + x）M_（2-x）O_4（M = Mn，Cr，Fe，Ni，x = 0 / 0.2），以确定在其它铜酸盐中观察到-MR的可能性并优化铜酸盐的磁阻特性。这项工作不仅具有重要的基础性意义，而且如果能够在更高的温度下观察到大的负磁阻，