Change of Magnetism in the Two-Dimensional Heisenberg Ferromagnet K2CuF4 Observed at High Pressures
Change of Magnetism in the Two-Dimensional Heisenberg Ferromagnet K2CuF4 Observed at High Pressures
复制标题
高压下观察到的二维海森堡铁磁体 K2CuF4 的磁性变化
DOI：
10.1143/jpsj.65.1927
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发表时间：
1996
影响因子：
1.7
通讯作者：
S. Endo
中科院分区：
文献类型：
--
作者：
M. Ishizuka;I. Yamada;K. Amaya;S. Endo
决定Cu 2+化合物中交换相互作用是铁磁或反铁磁的机制与Cu 2+空穴轨道的反铁畸变（AFD）或铁畸变（FD）序密切相关。K2 CuF 4是二维海森堡铁磁体的代表之一，具有理想的AFD轨道序.为了研究在高压下由于轨道序从AFD到FD的变化而引起磁相变的可能性，在1.5 ~ 18 K温度范围内，在13 GPa压力下对该化合物进行了磁化率测量。居里温度从7 GPa开始突然下降。此外，在10 GPa以上的压力下，观察到磁化率的大幅下降。这些结果表明，压力诱导铁磁反铁磁相变发生在约8-9 GPa的结果，从AFD到FD阶的轨道状态的变化。
The mechanism responsible for determining the exchange interaction to be ferromagnetic or antiferromagnetic in Cu 2+ compounds is closely correlated with the antiferrodistortive (AFD) or ferrodistortive (FD) order of Cu 2+ hole orbitals. One of the representative two-dimensional Heisenberg ferromagnets, K 2 CuF 4 , has an ideal AFD orbital ordering. To investigate the possibility of the magnetic phase transition due to a change in the orbital ordering from AFD to FD at high pressures, susceptibility measurements of this compound have been made under various pressures up to 13 GPa over the temperature range from 1.5 to 18 K. A sudden decrease in the Curie temperature starting from 7 GPa was observed. Furthermore, a large decrease in the susceptibility was observed at pressures above 10 GPa. These results indicate a pressure induced ferromagnetic to antiferromagnetic phase transition occurring at about 8–9 GPa as a result of a change of orbital state from AFD to FD order.