Magnetoelectric properties of LiCoPO4 and LiNiPO4
Magnetoelectric properties of LiCoPO4 and LiNiPO4
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DOI：
10.1103/physrevb.62.12247
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发表时间：
2000-11-01
影响因子：
3.7
通讯作者：
Wyder, P
中科院分区：
文献类型：
--
作者：
Kornev, I;Bichurin, M;Wyder, P
在高达20 T的强磁场中，在4.2 ~ 25 K的温度范围内，对LiNiPO_4单晶的磁致电极化进行了准静态测量。详细研究了Neel温度附近的磁电（ME）效应。发现了磁场诱导极化的温度滞后现象，在相变过程中观察到了反常的磁电磁化率温度依赖性和ME“蝴蝶环”。发展了LiCoPO_4和LiNiPO_4磁电效应的唯象理论。对磁电“蝴蝶环”的存在给出了初步的解释。它表明，有一个非Lifshitz不变量的自由能展开是线性的空间导数。因此，到空间调制自旋结构的相变是可能的。研究了这种结构对线性磁电效应的影响。
In strong magnetic fields up to 20 T quasistatic measurements of the magnetic-field-induced electric polarization have been performed in LiNiPO4 single crystals between 4.2 and similar to 25 K. The magnetoelectric (ME) effect has been studied in detail near the Neel temperature. The temperature hysteresis of the polarization induced by a magnetic field was found. An anomalous temperature dependence of the magnetoelectric susceptibility during the phase transition and the ME "butterfly loop" were observed. The phenomenological theory of the magnetoelectric effect in LiCoPO4 and LiNiPO4 has been developed. A tentative explanation of the existence of the magnetoelectric "butterfly loop" is given. It is shown that there is a non-lifshitz invariant in the free energy expansion which is linear in the spatial derivatives. Hence the phase transition to a space-modulated spin structure is possible. The influence of such a structure on the linear magnetoelectric effect is examined.