Tb3+ in TbCo3B2, a Singlet Ground State System, Studied by Inelastic Neutron Scattering
Tb3+ in TbCo3B2, a Singlet Ground State System, Studied by Inelastic Neutron Scattering
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DOI：
10.1103/physrevb.78.184424
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发表时间：
2008
影响因子：
3.7
通讯作者：
O. Rivin;R. Osborn;A. Kolesnikov;E. Caspi;H. Shaked
中科院分区：
文献类型：
--
作者：
O. Rivin;R. Osborn;A. Kolesnikov;E. Caspi;H. Shaked
报道了六方化合物TbCo3B2和Tb0.75Y0.25Co3B2在不同温度下的非弹性中子散射结果。确定了Tb3+离子在顺磁相中的晶场能级方案。该方案包含非磁性单态(G1)作为基态。在低温(10K)下的非弹性中子散射，导致了不同的能级方案，其中单重态基态是铁磁性的。这是Tb亚晶格上的一种“自感”铁磁性，是由于交换场将较高的晶场能级掺杂到单重态基态中而产生的。TbCo3B2和Tb0.75Y0.25Co3B2的基态磁矩分别为5.6(3)和3(1)Mub。这些值比9Mub的自由离子值小得多，与以前的观测值一致。如此大的缩减量是“自感”铁磁性的特征。讨论了磁矩、磁各向异性、Tb亚晶格稀释度和磁化率与温度的关系。
The results of inelastic neutron scattering on the hexagonal compounds TbCo3B2 and Tb0.75Y0.25Co3B2, at several temperatures are reported. The crystal field level scheme of Tb3+ ions in the paramagnetic phase is determined. This scheme contains a non-magnetic singlet (G1) as ground state. Inelastic neutron scattering at low temperature (10 K), leads to a different energy level scheme, where the singlet ground state is ferromagnetic with # 0. This is a "self induced" ferromagnetism on the Tb sub-lattice, resulting from the admixture of higher crystal field levels into the singlet ground state by the exchange field. The resulting magnitudes of these ground state magnetic moments are 5.6(3) and 3(1) muB for TbCo3B2 and Tb0.75Y0.25Co3B2, respectively. These values are much smaller than the free ion value of 9 muB and are in agreement with previously observed values. Such large reductions are characteristic of the "self induced" ferromagnetism. The temperature dependence of the magnetic moment, magnetic anisotropy, Tb sub-lattice dilution and magnetic susceptibility are discussed.