https://doi.org/10.1140/epjp/s13360-026-07735-0
Regular Article
Magnetic and hysteresis properties of the Spin-7/2 Blume–Capel model in the presence of a random crystal field
1
Institute of Mathematic and Physical Sciences (IMSP), Porto-Novo, Benin
2
Department of Physics, University of Abomey-Calavi, Godomey, Benin
3
Department of Physics, Erciyes University, 38039, Kayseri, Türkiye
4
Laboratory of Materials Science and Modeling, University of Abomey-Calavi, Godomey, Benin
5
ENS and Laboratory of Physics and Applications (LPA), UNSTIM d’Abomey, Abomey, Benin
6
Department of Physics, Faculty of Nature Sciences (FSN), University of Julius Nyerere of Kankan (UJNK), Kankan, Guinea
a
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Received:
17
March
2026
Accepted:
21
April
2026
Published online:
2
May
2026
Abstract
In this study, we rigorously investigate the spin-7/2 Ising Blume–Capel model subjected to randomly distributed single-ion anisotropy within a mean-field framework based on the Bogoliubov variational inequality. The ground-state phase diagram in the (
) plane reveals a rich hierarchy of magnetic phases, arising from the competition between the disorder strength 
and the crystal field parameter d. At finite temperatures, the system exhibits a complex phase topology characterized by first-and second-order phase transitions, reentrant behavior, and isolated critical points. These features originate from the interplay between thermal fluctuations, anisotropy, and quenched disorder, and are significantly enhanced compared to lower-spin systems. The magnetic response displays multiple magnetization plateaus together with a pronounced multi-loop hysteresis structure, stemming from metastable states associated with the multilevel nature of the spin-7/2 system and strongly amplified by disorder effects. Overall, the results highlight the key role of high spin and quenched disorder in generating rich and nontrivial magnetic behavior.
© The Author(s) 2026
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