Magnetic properties of TbMn6Sn6-xGax (x=0.0-1.2) compounds

• 来源期刊: 中国物理（英文版）
• 学科: 物理学
• 关键词: TbMn6Sn6-xGax compounds magnetic properties structure
• 年，卷（期）: 2002,（9）
• 页码范围: 955-959
• 页数: 5页
• 分类号: O4
• 语种: 英文

摘要

Effects of Ga substitution for Sn on the structure and magnetic properties of TbMn6Sn6-xGax (x=0.0-1.2)compounds have been investigated by means of x-ray diffraction, magnetization measurement and 119Sn Mossbauerspectroscopy. The substitution of Ga for Sn results in a decrease in lattice constants and unit-cell volumes. Themagnetic ordering temperature decreases monotonically with increasing Ga content from 423 K for x=0.0 to 390 K forx=1.2. At room temperature, the easy magnetization direction changes from the c-axis to the ab-plane. This variationimplies that the substitution of Ga for Sn leads to a decrease in the c-axis anisotropy of the Tb sublattice. An increasein the non-magnetic Ga concentration results in a monotonic decrease of the spontaneous magnetizationMs at roomtemperature. Since there are three non-equivalent Sn sites, 2c (0.33, 0.67,0), 2d (0.33, 0.67,0.5) and 2e (0,0,0.34) in theTbMn6Sn6-xGax compounds, the 119Sn Mossbauer spectra of the TbMn6Sn6 and TbMn6Sn5.4Ga0.6 compounds canbe fitted by three sextets. The hyperfine fields (HFs) decrease in the order of HF(2d)＞HF(2e)＞HF(2c), which is inagreement with the magnetic structure.