Successive magnetic phase transitions of component orderings in DyB4
Successive magnetic phase transitions of component orderings in DyB4
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DyB4 中组分顺序的连续磁相变
DOI：
10.1143/jpsj.80.074701
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
and Y. Murakami
中科院分区：
文献类型：
--
作者：
T. Matsumura;D. Okuyama;T. Mouri;and Y. Murakami
用共振X射线衍射和中子散射的微观测量方法详细研究了DyB_4的连续磁相变。结果表明，在轴向分量为长程有序的中间相，磁矩的ab面分量为短程有序。据估计，这种短程有序是动态波动的时间尺度之间的10- 8至10- 11秒。用非弹性中子散射研究了晶体场的激发。为了定性地理解相变现象，我们用平均场计算方法研究了一个简单的具有反铁磁相互作用的两子晶格模型。计算虽然没有考虑四极相互作用，但成功地解释了双相变、磁比热和磁熵、磁化率以及中间相的巨大弹性软化的发生。平均场计算的一般成功，除了短程秩序，表明在零磁场的宏观性质上的几何挫折的影响很小。
The successive magnetic phase transitions in DyB4have been studied in detail by microscopic measurements using resonant X-ray diffraction and neutron scattering. It is shown that theab-plane component of the magnetic moment is short-range-ordered in the intermediate phase where thec-axis component is long-range-ordered. It is estimated that this short-range order is dynamically fluctuating with a time scale between ∼10-8to ∼10-11s. Crystal field excitation has also been investigated by inelastic neutron scattering. To qualitatively understand the phase-transition phenomenon, we have studied a simple two-sublattice model with an antiferromagnetic interaction by mean-field calculation. The calculation, though without a quadrupolar interaction, successfully explains the occurrence of double phase transition, magnetic specific heat and entropy, magnetic susceptibility, and the huge elastic softening in the intermediate phase. The general success of the mean-field calculation, except for the short-range order, suggests that there is little effect of geometrical frustration on the macroscopic properties at zero magnetic field.