Incommensurate-commensurate transitions in the monoaxial chiral helimagnet driven by the magnetic field
Incommensurate-commensurate transitions in the monoaxial chiral helimagnet driven by the magnetic field
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DOI：
10.1103/physrevb.93.134424
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发表时间：
2016-04-20
影响因子：
3.7
通讯作者：
Inoue, Katsuya
中科院分区：
文献类型：
--
作者：
Laliena, Victor;Campo, Javier;Inoue, Katsuya
深入分析了单轴手性螺旋网在平行和垂直于螺旋轴的分量所形成的磁场平面内的零温相图。跃迁到公度态的性质取决于场和螺旋轴之间的角度。对于与螺旋轴平行或垂直的近场方向，跃迁是连续的，而对于中间角，跃迁是不连续的，无公度态和公度态共存于过渡线上。连续和不连续的过渡线由两个具有特定奇异行为的三临界点隔开。连续线、不连续线和三临界点的位置强烈依赖于易平面各向异性，并分析了易面各向异性的影响。对于高各向异性，锥形近似可以非常准确地定位相变线，尽管它不能预测连续相变和三临界行为。结果表明，对于高各向异性，如在CrNb3S6中，过渡线的形式是通用的，即与样品无关，并服从一个简单的方程。对于CrNb3S6样品，理论上估计了三临界点的位置，但这并不是通用的。
The zero-temperature phase diagram of the monoaxial chiral helimagnet in the magnetic-field plane formed by the components parallel and perpendicular to the helical axis is thoroughly analyzed. The nature of the transition to the commensurate state depends on the angle between the field and the helical axis. For field directions close to the directions parallel or perpendicular to the helical axis the transition is continuous, while for intermediate angles the transition is discontinuous and the incommensurate and commensurate states coexist on the transition line. The continuous and discontinuous transition lines are separated by two tricritical points with specific singular behavior. The location of the continuous and discontinuous lines and of the tricritical points depend strongly on the easy-plane anisotropy, the effect of which is analyzed. For high anisotropy the conical approximation locates the transition line very accurately, although it does not predict the continuous transitions and the tricritical behavior. It is shown that for high anisotropy, as in CrNb3S6, the form of the transition line is universal, that is, independent of the sample, and obeys a simple equation. The position of the tricritical points, which is not universal, is theoretically estimated for a sample of CrNb3S6.