Abstract

The concentration and temperature transitions in strongly correlated Fe_1 – xCo_xSi alloys with the Dzyaloshinski–Moriya (DM) interaction are considered in terms of the spin-fluctuation theory taking into account the results of LDA + U + SO calculations of the density of electronic states. It is shown that the concentration order–order transitions with change in the sign of the left spin chirality (at x < 0.2) to the right that (at x ≤ 0.2x < 0.65, and again to the left chirality at x ≥ 0.65 are related to the change in the sign of the parameter of the mode–mode interaction. It is also shown that, in the composition range of Fe_1 – xCo_xSi with 0.2 ≤ x < 0.65, the first-order transitions extended in temperature arise, accompanied by the appearance of an intermediate temperature range of the spin short-range order with a noncompensated local magnetization and the DM interaction. In an external magnetic field, in this temperature range at 0.2 ≤ x < 0.65, skyrmion microstructures arise. At x = 0.65, the mode–mode interaction parameter becomes be zero, the long-range order becomes ferromagnetic (since the experiment demonstrates the compensation of the DM interaction), and a temperature second-order transition appears instead of the extended first-order transition. The (h–T) diagrams of magnetic states of Fe_1 – xCo_xSi have been constructed; they agree with the experiment.

中文翻译：

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具有扰动的晶体B20型结构的强相关Fe 1 – x Co x Si中的涨落诱导相变和Skyrmion

摘要

考虑自旋涨落理论，考虑到LDA + U + SO对密度的计算结果，考虑了具有Dzyaloshinski-Moriya（DM）相互作用的高度相关的Fe _{1 –  x} Co _x Si合金的浓度和温度转变。电子状态。结果表明，与在左旋手性的符号改变的浓度阶阶转变（在X <0.2），其（在合适的X ≤0.2 X <0.65，并再次向左侧在手性X ≥0.65是与模式-模式相互作用参数符号的变化有关，也表明，在Fe _{1-  x} Co的组成范围内_X的Si 0.2≤  X <0.65时，第一级转变延伸温度出现，伴随着中间温度范围内的自旋短程有序的外观与无补偿局部磁化和DM相互作用。在外部磁场中，在此温度范围内，以0.2≤ X <0.65，skyrmion微结构产生。在x = 0.65时，模-模相互作用参数变为零，长程阶变为铁磁（因为实验证明了DM相互作用的补偿），并且出现了温度二阶跃迁而不是扩展的一阶跃迁。过渡。Fe _1-的磁态（ h - T）图 _x Co _x Si已构建；他们同意实验。