Physics, mathematics, and technology

2020 Issue №3

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Hysteresis loops for a bulk ferromagnetic by Hei­senberg model



In a framework of Heisenberg theory, that link quantum-statistical des­crip­tion taking Gauss distribution into account, explicit form is obtained by per­mutations group theory, the division paramagnetic/ferromagnetic is stu­died. The magnetization curves are built for a given set of parameters, such as exchange integral, number of closest neighbours and temperature. In a special ran­ge of the parameters a transition from unique solution of the resulting Hei­senberg equation to multi-valued is observed. For this case exemplary hys­te­resis loops are built. The expression for Curie temperature allows to evaluate the exchange integral and proceed into temperature range above the critical temperature.