Magnetism and magnetoresistance of Er1-x SmxMn6Ge6 (x＝0.2-1.0) compounds

• 来源期刊: 中国物理（英文版）
• 关键词: magnetism positive magnetoresistance
• 年，卷（期）: 2004,（7）
• 页码范围: 1129-1133
• 页数: 5页
• 语种: 英文

摘要

Magnetic and transport properties of Erl-xSmxMn6Ge6 (x＝0.2-1.0) have been investigated by x-ray diffraction (XRD) and magnetization measurement. Analysis of the XRD patterns indicates that the samples with x ≤ 0.4 mainly consist of HfFe6Ge6-type phase and the samples with 0.6≤ x ≤1.0 mainly consist of YCo6Ge6-type phase (P6/mmm).The lattice constants and the unit cell volume increase with increasing Sm content. The antiferro-ferri-ferromagnetic transitions can be observed with increasing Sm content. The samples with x＝0.2 and 0.4 order antiferromagnetically at 420 and 425K, respectively. The samples with x＝0.6, 0.8 and 1.0 order from ferri- to ferromagnetically over the whole magnetic ordering temperature range. The corresponding Curie temperatures are 435, 441 and 446K, respectively. The magnetoresistance (MR) isotherms of the sample with x＝0.8, measured at various temperatures, are analysed. The magnitude of MR is found to be positive below 55K and gradually increases to a relatively large value of about 5.02%at 5K in a field of 5T as the temperature is lowered. A possible explanation for the positive MR is given.