Dielectric, magnetic, and magnetotransport properties in Sr doped two-dimensional RE2CoO4 (RE=Pr,Eu) compounds
Dielectric, magnetic, and magnetotransport properties in Sr doped two-dimensional RE2CoO4 (RE=Pr,Eu) compounds
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DOI：
10.1063/1.2830797
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发表时间：
2008-01
影响因子：
3.2
通讯作者：
Q. Yao;Xiaolin Wang;S. Dou
中科院分区：
文献类型：
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作者：
Q. Yao;Xiaolin Wang;S. Dou
在这项工作中，我们报告了 Sr 掺杂 RE2−xSrxCoO4（RE=Pr 或 Eu，x=0.25–1.5）的介电、磁性和磁输运特性的研究。这些化合物在结构、磁性、磁输运和介电常数测量方面进行了系统研究。 Rietveld精修表明这些化合物结晶为K2NiF4型结构，空间群为I4∕mmm。晶格参数随着 Sr 掺杂水平的增加而增加。随着Sr掺杂水平的增加，系统从顺磁性变为铁磁性，最终变为铁磁性，Pr0.75Sr1.25CoO4和EuSrCoO4的TC分别为230K。电阻率的温度依赖性表明，通过 Sr 掺杂，两个体系都从半导体转变为金属。 EuSrCoO4 化合物在 5K 和 8T 下的磁阻 (MR) 值为 10%。对于基于 Pr 的化合物，x 约为 1 的样品在低频下观察到介电常数值高于 2000。
In this work, we report on the studies of dielectric, magnetic, and magnetotransport properties of Sr doped RE2−xSrxCoO4 (RE=Pr or Eu, x=0.25–1.5). These compounds were systematically studied in terms of structure, magnetic, magnetotransport, and dielectric constant measurements. Rietveld refinement indicated that these compounds crystallized in K2NiF4-type structure with space group I4∕mmm. Lattice parameters increase with Sr doping level. The system changes from paramagnetic to ferromagnetic with increasing Sr doping level and finally becomes ferromagnetic with TC of 230K for Pr0.75Sr1.25CoO4 and EuSrCoO4, respectively. The temperature dependence of resistivity indicates that both systems change from semiconductive to metallic with Sr doping. The magnetoresistance (MR) value of 10% at 5K and 8T is found for the EuSrCoO4 compound. Large dielectric constants with values of above 2000 were observed in low frequencies for samples with x around 1 for Pr based compounds.