Phase diagrams of a magnet with competing types of anisotropy: Entropy modeling and machine learning

Phase diagrams of a magnet with competing types of anisotropy: Entropy modeling and machine learning Full article

Journal

EPL
ISSN: 0295-5075 , E-ISSN: 1286-4854

Output data

Year: 2026, Volume: 156, Article number : 46003, Pages count : 7 DOI: 10.1209/0295-5075/ae9dae

Authors

Khitrintseva V.V. ¹ , Druzev D.A. ¹ , Prudnikov P.V. ^1,2

Affiliations

1	Department of Theoretical Physics, Dostoevsky Omsk State University
2	Center of New Chemical Technologies BIC, Boreskov Institute of Catalysis

Funding (1)

Ministry of Science and Higher Education of the Russian Federation

FWUR-2024-0039

We investigate critical behavior of the Heisenberg model with competing exchange and single-ion crystalline anisotropy with parameter D. We reconstruct the complete D-T phase diagram using the joint density of states, which was calculated by the Wang-Landau algorithm. A hybrid approach involved entropy modeling with unsupervised machine learning methods is proposed for automatic identification of magnetic ordering phases and determination of bicritical point coordinates (Tbc, Dbc ). V-shaped phase coexistance boundaries, corresponding to competition between XY -like and Ising-like order were reveald for D ∼ Dc with three types of transitions: classic second-order transitions between paramagnetic and ordered phases, first-order transition line between XY and Ising phases and crossover from Ising to paramagnetic phase at non-zero external magnetic field. The proposed approach allows for the precise detection of phase boundaries and multicritical points.

Khitrintseva V.V. , Druzev D.A. , Prudnikov P.V.
Phase diagrams of a magnet with competing types of anisotropy: Entropy modeling and machine learning
EPL. 2026. V.156. 46003 :1-7. DOI: 10.1209/0295-5075/ae9dae

Submitted:	May 27, 2026
Accepted:	Aug 24, 2026
Published online:	Sep 30, 2026

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