论文标题
在铁磁超导体uge $ _2 $的磁相变压力上的压力对现象学方法 - 现象学方法
Infuence of pressure on magnetic phase transitions in the ferromagnetic superconductor UGe$_2$ -- phenomenological approach
论文作者
论文摘要
我们提出了一个自由能扩展的热力学模型，高达第八次磁化阶，以描述铁磁超导体UGE $ _2 $中的复杂磁相变。该模型成功地描述了在没有磁性结构的情况下发生的有序相之间的过渡，但仅具有磁性，这是UGE $ _2 $的情况，其中两个具有相同结构的磁相，但随着温度降低而发生不同的幅度。我们认为，最简单形式的压力对磁性转变的压力仅在库里温度的压力依赖性中包括对磁磁相和磁相之间的过渡，而磁矩较低的磁矩FM1。我们的结果表明，对于低于某些限制压力的压力，跨界类型的横向和高磁化阶段之间的过渡阶段。高于这种限制压力，这种过渡会变为一阶的实际热力学转变。
We propose a thermodynamic model of free energy expansion up to eighth order of magnetisation to describe the complex magnetic phase transitions in ferromagnetic superconductor UGe$_2$. The model successfully describes transitions between ordered phases which take place without changing of magnetic structure but only of magnetisation which is the case of UGe$_2$ where two magnetic phases with same structure but with different magnitude occur with decreasing of temperature. We consider the infuence of pressure on magnetic transitions in the simplest form of including it only in pressure dependence of Curie temperature for the transition between the paramagnetic and themagnetic phase with the lower magnetic moment FM1. Our results show that for pressures lower than some limiting pressure the transition betweenlow-and high-magnetisation phase remains of crossover type. Above this limiting pressure this transition changes to real thermodynamic transition of first order.
