Magnetic properties and electronic structure of R3T4X4 (R: La–Nd, Gd–Er; T: Mn, Cu; X: Ge, Sn) compounds
Magnetic properties and electronic structure of R3T4X4 (R: La–Nd, Gd–Er; T: Mn, Cu; X: Ge, Sn) compounds
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DOI：
10.1016/j.jallcom.2003.08.042
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发表时间：
2004-03
影响因子：
6.2
通讯作者：
A. Szytuła;E. Wawrzyńska;B. Penc;N. Stüsser;Z. Tomkowicz;A. Zygmunt
中科院分区：
文献类型：
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作者：
A. Szytuła;E. Wawrzyńska;B. Penc;N. Stüsser;Z. Tomkowicz;A. Zygmunt
本文报道了一系列新的金属间化合物R_3T_4X_4（R：La-Nd，Gd-Er; T：Mn，Cu; X：Ge，Sn）的磁衍射和中子衍射研究结果。这些化合物以正交晶系Gd 3Cu 4Ge 4型结构（空间群Imm）结晶。稀土原子占据两个不等价的晶体学位置。所研究的化合物均为反铁磁体。在R_3Mn_4Sn_4系列中，稀土和锰的磁矩在不同温度下有顺序排列：稀土磁矩在25 K（R：Pr）和60 K（R：Nd）有顺序排列，锰磁矩在300 K（La）、230 K（Pr）和210 K（Nd）有顺序排列。R3 Cu 4Ge 4化合物是反铁磁体，Néel温度在23 K（对于Tb 3Cu 4Ge 4）和5.9K（对于Er 3Cu 4Sn 4）之间。对于Tb_3Cu_4Ge_4、Er_3Cu_4Ge_4、Ho_3Cu_4Sn_4和Er_3Cu_4Sn_4，在低于Néel温度时发生进一步的相变。磁矩只局限于稀土原子上。在不同的温度下，位于不同晶位的磁矩具有不同的值和顺序。用X射线光电子能谱（XPS）研究了Gd_3Cu_4X_4（X：Ge，Sn）的电子结构。价带的复杂性影响了这些化合物的磁性。
The results of magnetic and neutron diffraction studies of a new series of intermetallic compounds R3T4X4(R: La–Nd, Gd–Er; T: Mn, Cu; X: Ge, Sn) are presented. These compounds crystallize in the orthorhombic Gd3Cu4Ge4-type structure (space group Immm). The rare earth atoms occupy two non-equivalent crystallographic positions. All the investigated compounds are antiferromagnets. In the R3Mn4Sn4series the rare earth and the manganese magnetic moments order at different temperatures: the rare earth moments order at 25K (R: Pr) and 60K (R: Nd), while the manganese moments order at 300K (La), 230K (Pr) and 210K (Nd). The R3Cu4Ge4compounds are antiferromagnets with Néel temperatures between 23K (for Tb3Cu4Ge4) and 5.9K (for Er3Cu4Sn4). For Tb3Cu4Ge4, Er3Cu4Ge4, Ho3Cu4Sn4and Er3Cu4Sn4further phase transitions occur below the Néel temperature. The magnetic moments are localized only on the rare earth atoms. The moments located at different crystallographic sites have different values and order at different temperatures. The electronic structure of Gd3Cu4X4(X: Ge, Sn) was studied by X-ray photoemission spectroscopy (XPS). The complex character of the valence band influences the magnetic properties of these compounds.