Possible ordering of Ru and Cu in the charge-reservoir of magneto-superconductor RuSr2GdCu2O8 (Ru-1212): Magnetic, transport, and TEM microstructural studies
Possible ordering of Ru and Cu in the charge-reservoir of magneto-superconductor RuSr2GdCu2O8 (Ru-1212): Magnetic, transport, and TEM microstructural studies
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磁超导体 RuSr2GdCu2O8 (Ru-1212) 电荷库中 Ru 和 Cu 的可能排序：磁性、输运和 TEM 微观结构研究
DOI：
10.1063/1.1456444
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发表时间：
2002
影响因子：
3.2
通讯作者：
S. Malik
中科院分区：
文献类型：
--
作者：
V. Awana;S. Ichihara;J. Nakamura;M. Karppinen;H. Yamauchi;Jinbo Yang;W. Yelon;W. James;S. Malik
在5 Oe的电场中测量的RuSr2GdCu2O8−δ (Ru-1212)的磁化温度行为表明，在140 K左右出现了明显的零场冷却（ZFC）和场冷却（FC）曲线分支，在135 K时出现了一个尖点，在20 K左右出现了反磁转变（在ZFC分支中）。在135k处的尖峰是由于Ru矩的反铁磁顺序。在50 K以下，磁场等温线显示出铁磁分量的非线性贡献。在0、3和7 T的电场中，化合物的电阻对温度的行为证实了样品在20 K左右是超导的。超导跃迁表现出一种不同于传统高Tc超导体的场展宽类型。在135 K以上，磁电阻为负，在135 K以下，磁电阻在低场呈正峰，在高场呈负峰。在Ru磁有序温度下，最大可观察到2%的负MR值。Ru-1212样品的电子衍射图显示出两种类型的上层结构；一个在a - b矩形的中心有一个弱点，另一个只沿着b方向。有可能Ru/Cu或Ru4+/Ru5+沿b方向发生2b周期性排序。在5 Oe的电场中测量的RuSr2GdCu2O8−δ (Ru-1212)的磁化温度行为表明，在140 K左右出现了明显的零场冷却（ZFC）和场冷却（FC）曲线分支，在135 K时出现了一个尖点，在20 K左右出现了反磁转变（在ZFC分支中）。在135k处的尖峰是由于Ru矩的反铁磁顺序。在50 K以下，磁场等温线显示出铁磁分量的非线性贡献。在0、3和7 T的电场中，化合物的电阻对温度的行为证实了样品在20 K左右是超导的。超导跃迁表现出一种不同于传统高Tc超导体的场展宽类型。在135 K以上，磁电阻为负，在135 K以下，磁电阻在低场呈正峰，在高场呈负峰。在Ru磁极处观察到最大2%的负MR值。
Magnetization vs temperature behavior of RuSr2GdCu2O8−δ (Ru-1212) measured in an field of 5 Oe, shows a clear branching of zero-field-cooled (ZFC) and field-cooled (FC) curves around 140 K, a cusp at 135 K, and a diamagnetic transition around 20 K (in the ZFC branch). The cusp at 135 K is due to the antiferromagnetic ordering of the Ru moments. The magnetization-field isotherms, below 50 K, show a nonlinear contribution from a ferromagnetic component. The resistance vs temperature behavior of the compound, in applied fields of 0, 3, and 7 T, confirms that the sample is superconducting at around 20 K. The superconducting transition exhibits field broadening of a type different than that known for conventional high Tc superconductors. The magnetoresistance (MR) is negative above the Ru magnetic ordering temperature of 135 K, while below this temperature, MR displays a positive peak in low fields and becomes negative in higher fields. A maximum of 2% is observed for the negative MR value at the Ru magnetic ordering temperature. An electron diffraction pattern obtained for this Ru-1212 sample shows two types of superstructure; one with a weak spot at the center of the a–b rectangle and the other only along the b direction. It is possible that either Ru/Cu or Ru4+/Ru5+ ordering of 2b periodicity takes place along the b direction.Magnetization vs temperature behavior of RuSr2GdCu2O8−δ (Ru-1212) measured in an field of 5 Oe, shows a clear branching of zero-field-cooled (ZFC) and field-cooled (FC) curves around 140 K, a cusp at 135 K, and a diamagnetic transition around 20 K (in the ZFC branch). The cusp at 135 K is due to the antiferromagnetic ordering of the Ru moments. The magnetization-field isotherms, below 50 K, show a nonlinear contribution from a ferromagnetic component. The resistance vs temperature behavior of the compound, in applied fields of 0, 3, and 7 T, confirms that the sample is superconducting at around 20 K. The superconducting transition exhibits field broadening of a type different than that known for conventional high Tc superconductors. The magnetoresistance (MR) is negative above the Ru magnetic ordering temperature of 135 K, while below this temperature, MR displays a positive peak in low fields and becomes negative in higher fields. A maximum of 2% is observed for the negative MR value at the Ru magnetic o...