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Magnetic phase separation in La0.8Pr0.2Fe13.7Si1.3-Hδ alloys induced by long-term exposure to cyclic magnetic fields: Direct measurements of adiabatic temperature change in cyclic magnetic fields up to 8 Tстатья Исследовательская статья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 1 октября 2025 г.
- Авторы: Gamzatov Adler, Abdulkadirova Nurizhat, Igoshev Petr, Tsymbarenko Dmitry, Aliev Akhmed, Wang Jing, Hu Feng-xia
- Журнал: Journal of Alloys and Compounds
- Том: 1040
- Год издания: 2025
- Издательство: Elsevier BV
- Местоположение издательства: Netherlands
- Номер статьи: 183453
- DOI: 10.1016/j.jallcom.2025.183453
- Аннотация: We present a study of the effect of low-frequency cyclic magnetic fields with amplitude up to 8 T on the magnetic, magnetocaloric and thermophysical properties of the La0.8Pr0.2Fe13.7Si1.3-Hδ alloys. Direct measurements of the adiabatic temperature change ΔTad were performed in cyclic magnetic fields. The specific heat and thermal diffusivity were measured in magnetic fields of 0, 0.62 and 1.8 T in the vicinity of Curie temperature TC. An anomalous peak and satellite anomalies temperature dependence of the specific heat in a magnetic field are observed in a close vicinity of ТС. These anomalies are the result of sample degradation in cyclic magnetic field during corresponding ΔTad measurements. We interpret this as a consequence of a multiphase state (magnetic phase separation) with spatially distributed critical temperatures caused by a cyclic magnetic field. Long-term exposure to a 1.8 T cyclic magnetic field at a frequency of 0.2 Hz leads to a slight decrease in ΔTad of 0.13 and 0.57 K for La0.8Pr0.2Fe13.7Si1.3 and La0.8Pr0.2Fe13.7Si1.3Hδ, respectively, followed by a stabilization of the effect. In a magnetic field of 8 T, ΔTad shows good stability up to 1000 cycles. The maximum value of ΔTad reaches 12.7 and 10.9 K at magnetic field value H = 8 T for La0.8Pr0.2Fe13.7Si1.3 and La0.8Pr0.2Fe13.7Si1.3Hδ, respectively. In contrast to the case of small magnetic fields, the value of ΔTad for both samples exhibits the temporal stability in strong cyclic magnetic fields with amplitude 8 T. A correlation between changes in the Fe–Fe bond lengths and MCE degradation was confirmed using XRD analysis. The strong difference of intra-icosahedral distances reduction of the Fe–Fe bonds for La0.8Pr0.2Fe13.7Si1.3 (0.007–0.008 Å) and La0.8Pr0.2Fe13.7Si1.3Hδ, (0.013 Å) in the vicinity phase transition temperature is revealed. This enhanced response of the Fe–Fe bond distance to cyclic application of a magnetic field allows to explain stronger degradation of the MCE in La0.8Pr0.2Fe13.7Si1.3Hδ.
- Добавил в систему: Цымбаренко Дмитрий Михайлович
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