Synthesis and study of electronic state of Sr2CrO2Co2As2 with CoAs conduction layers
Synthesis and study of electronic state of Sr2CrO2Co2As2 with CoAs conduction layers
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DOI：
10.1088/1742-6596/868/1/012024
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发表时间：
2017-06
期刊：
影响因子：
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通讯作者：
A. Suzuki;H. Ohta;H. Katori
中科院分区：
文献类型：
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作者：
A. Suzuki;H. Ohta;H. Katori
我们成功地合成了一种新的具有CoAs层的化合物Sr2CrO2Co2As2及其部分替代系统Sr2CrO2（TmxCo1−x）2As2（Tm = Fe，Ni），并测量了这些多晶化合物的磁化强度和电阻率。作为Sr_2CrO_2Co_2As_2的磁性测量结果，Co的磁矩不像其他具有CoPn（Pn=P和As）层的化合物那样构成巡回电子铁磁性。两个Sr2CrO2（TmxCo1−x）2As2（Tm = Fe）和Ni在低于2K的温度下也没有显示出巡游的电子铁磁性。对于x > 0.0的Sr2CrO2（FexCo1−x）2As2固溶体，在低温区ρ随T的降低而微弱增大，表明Cr和Fe在Sr2CrO2（FexCo1−x）2As2中的导电层内发生了混合占位。我们的结论是，Sr2CrO2Co2As2中铁磁性的缺失是由于从Cr到导带的自电子掺杂，并且通过空穴掺杂效应恢复铁磁性的尝试被Cr和Fe在Sr2CrO2（FexCo1−x）2As2中的混合占据阻止，其中x > 0.0。结构分析结果支持了Sr_2CrO_2Co_2As_2中巡游电子铁磁性消失的原因是Cr的自电子掺杂。
We successfully synthesized a new member of compounds with the CoAs layer, Sr2CrO2Co2As2, and its partially substituted systems Sr2CrO2(TmxCo1−x)2As2 (Tm = Fe, Ni), and measured magnetization and electric resistivity of these polycrystalline compounds. As a result of magnetic measurement for Sr2CrO2Co2As2, magnetic moments of Co do not construct an itinerant electronic ferromagnetism unlike other compounds with the CoPn (Pn=P and As) layers. Both Sr2CrO2(TmxCo1−x)2As2 with Tm = Fe and Ni also do not show an itinerant electronic ferromagnetism down to 2 K. For each solid solution of Sr2CrO2(FexCo1−x)2As2 with x > 0.0, ρ weakly increases with the decrease of T at low temperature region, indicating that the mixed occupancy of Cr and Fe within the conducting layers occurs in Sr2CrO2(FexCo1−x)2As2. We conclude that the absence of ferromagnetism in Sr2CrO2Co2As2 is due to the self-electron-doping from Cr to the conduction bands and the attempt to recover the ferromagnetism by the hole-doping effect is prevented by the mixed occupancy of Cr and Fe in Sr2CrO2 (FexCo1−x)2As2 with x > 0.0. The result of our structural analysis supports that the disappearance of itinerant electronic ferromagnetism in Sr2CrO2Co2As2 is due to the self-electron-doping from Cr.