Please use this identifier to cite or link to this item: http://er.nau.edu.ua:8080/handle/NAU/35239
Title: Change in the entropy during a first-order phase transition induced by a magnetic field in an isotropic non-Heisenberg ferromagnet
Authors: Лаванов, Геннадій Юрійович
Keywords: magnetic
phase
transitions
quantum
Issue Date: Apr-2018
Publisher: AIP Publishing
Citation: Low Temperature Physics 44, 322 (2018); doi: 10.1063/1.5030455
Abstract: We describe a first-order phase transition in an isotropic non-Heisenberg ferromagnet induced by a magnetic field with a fourth-order spin exchange interaction at temperatures above the Curie point. The field behavior of the magnetization is analyzed and the temperature dependences of the critical fields of the stability of the paramagnetic and ferromagnetic phases as well as the critical field of the phase transition between them are determined. It is shown that this first-order phase transition has a finite amplitude of the magnetization jump and can occur in small magnetic fields. An H–T phase diagram is presented. It is found that the amplitude of the phase jump during the magnetic field-induced transition from the paramagnetic to the ferromagnetic phase can exceed the magnitude of the entropy change of an isotropic Heisenberg ferromagnet by two orders of magnitude when it is magnetized at the Curie point. It is shown that the expansion of the free energy model up to the 6th power in magnetization can only qualitatively describe the entropy behavior in the phase transition between the paramagnetic and ferromagnetic phases.
URI: http://er.nau.edu.ua:8080/handle/NAU/35239
Appears in Collections:Наукові публікації кафедри загальної фізики

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