Confinement of chiral magnetic modulations in the precursor region of FeGe
Confinement of chiral magnetic modulations in the precursor region of FeGe
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DOI：
10.1088/0953-8984/24/29/294204
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发表时间：
2012-03
期刊：
影响因子：
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通讯作者：
H. Wilhelm;M. Baenitz;M. Schmidt;C. Naylor;R. Lortz;U. Rößler;A. A. Leonov-A.;A. Bogdanov
中科院分区：
文献类型：
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作者：
H. Wilhelm;M. Baenitz;M. Schmidt;C. Naylor;R. Lortz;U. Rößler;A. A. Leonov-A.;A. Bogdanov
本文报道了立方磁晶FeGe的磁化率和比热在Tc=278.2(3)K的外磁场和长程磁序开始附近的温度下的测量。在依赖于场的χAc(H)数据以及相应的虚部χ“Ac(H)”中的显著反常揭示了磁相图中围绕Tc的前驱区域。在零场比热数据中，在T0=279.6 K处出现极大值表明发生了向磁有序状态的二级转变。当施加磁场时，肩部会演化到这个最大值以上。这两个特征的场依赖关系与恒定磁场下χAc(T)从场极化到顺磁态的交叉线相吻合。实验结果是在标准的Dzyaloshinskii立方日面成像网理论范围内分析的。通过该区域内孤子核间相互作用性质的变化和特定受限手性调制的开始，解释了调制前驱态的显著多样性和磁有序附近磁相图的复杂性。
We report on magnetic susceptibility and specific heat measurements of the cubic helimagnet FeGe in external magnetic fields and temperatures near the onset of long-range magnetic order at TC = 278.2(3) K. Pronounced anomalies in the field-dependent χac(H) data as well as in the corresponding imaginary part χ″ac(H) reveal a precursor region around TC in the magnetic phase diagram. The occurrence of a maximum at T0 = 279.6 K in the zero-field specific heat data indicates a second-order transition into a magnetically ordered state. A shoulder evolves above this maximum as a magnetic field is applied. The field dependence of both features coincides with crossover lines from the field-polarized to the paramagnetic state deduced from χac(T) at constant magnetic fields. The experimental findings are analyzed within the standard Dzyaloshinskii theory for cubic helimagnets. The remarkable multiplicity of modulated precursor states and the complexity of the magnetic phase diagram near the magnetic ordering are explained by the change of the character of solitonic inter-core interactions and the onset of specific confined chiral modulations in this area.