arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0812.4330cond-mat.str-el
收藏

金属间硼碳化物TbCo2B2C的铁磁结构

On the ferromagnetic structure of the intermetallic borocarbide TbCo2B2C

M. ElMassalami, R. Moreno, R. M. Saeed, F. A. B. Chaves, C. M. Chaves, H. Takeya, B. Ouladdiaf, M. Amara

摘要:

基于磁化,比热,磁致伸缩,和中子衍射研究的单晶TbCo 2B 2C,它被发现的顺磁性,液氮温度下,很好地描述了居里-外斯行为的Tb+3时刻。此外,低于Tc= 6.3 K,Tb亚晶格经历铁磁(FM)相变,易磁化轴沿着(100)方向,并且伴随着,晶胞经历四方到正交畸变。对于高达90 kOe的磁场,没有观察到Co 3d轨道的场致分裂;因此,内部磁场必须远低于使Co 3d子系统稳定所需的临界值。FM状态的表现在TbCo 2B 2C是唯一的所有其他同晶硼碳化物,特别是TbNi 2B 2C(Tn=15 K,无公度调制的磁状态),即使在两个同晶型的Tb-离子具有几乎相同的晶体电场属性。这些Tb基同构的磁模式的差异是由于它们的晶格参数和费米能级的位置的变化引起的交换耦合的差异。

英文摘要:

Based on magnetization, specific heat, magnetostriction, and neutron diffraction studies on single-crystal TbCo2B2C, it is found out that the paramagnetic properties, down to liquid nitrogen temperatures, are well described by a Curie-Weiss behavior of the Tb+3 moments. Furthermore, below Tc= 6.3 K, the Tb-sublattice undergoes a ferromagnetic (FM) phase transition with the easy axis being along the (100) direction and, concomitantly, the unit cell undergoes a tetragonal-to-orthorhhombic distortion. For fields up to 90 kOe, no field-induced splitting of the Co 3d orbitals was observed; as such the internal field must be well below the critical value needed to polarize the Co 3d subsystem. The manifestation of a FM state in TbCo2B2C is unique among all other isomorphous borocarbides, in particular TbNi2B2C (Tn=15 K, incommensurate modulated magnetic state) even though the Tb-ions in both isomorphs have almost the same crystalline electric field properties. The difference in the magnetic modes of these Tb-based isomorphs is attributed to a difference in their exchange couplings caused by a variation in their lattice parameters and in the position of their Fermi levels.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑