Magnetoelastic effects in Jahn-Teller distorted CrF2 and CuF2 studied by neutron powder diffraction
Magnetoelastic effects in Jahn-Teller distorted CrF2 and CuF2 studied by neutron powder diffraction
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DOI：
10.1088/0953-8984/23/27/276007
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发表时间：
2011-07-11
影响因子：
2.7
通讯作者：
Hansen, Thomas C.
中科院分区：
文献类型：
--
作者：
Chatterji, Tapan;Hansen, Thomas C.
利用中子粉末衍射研究了jhn - teller扭曲过渡金属二氟化物CrF2和CuF2在2 ~ 280 K温度范围内晶体结构和磁性结构的温度依赖性。在尼尔温度下，晶格参数和晶胞体积表现出磁弹性效应。由磁致伸缩效应引起的晶格应变与反铁磁相变序参量的平方耦合。我们还研究了Jahn-Teller畸变的温度依赖性，该畸变在反铁磁相变中没有表现出任何显著的影响，但在CrF2中随着温度的升高而线性增加，而在CuF2中几乎与温度无关。随着过渡金属离子低温饱和磁矩的增大，其磁体积效应的大小似乎增大，但相关性并不完全。
We have studied the temperature dependence of the crystal and magnetic structures of the Jahn-Teller distorted transition metal difluorides CrF2 and CuF2 by neutron powder diffraction in the temperature range 2-280 K. The lattice parameters and the unit cell volume show magnetoelastic effects below the Neel temperature. The lattice strain due to the magnetostriction effect couples with the square of the order parameter of the antiferromagnetic phase transition. We also investigated the temperature dependence of the Jahn-Teller distortion, which does not show any significant effect at the antiferromagnetic phase transition but increases linearly with increasing temperature for CrF2, and remains almost independent of temperature in CuF2. The magnitude of magnetovolume effect seems to increase with the low temperature saturated magnetic moment of the transition metal ions but the correlation is not at all perfect.