Phase Boundary Near a Magnetic Percolation Transition

Author

Gaurav Khairnar
Cameron Lerch
Thomas Vojta, Missouri University of Science and TechnologyFollow

Abstract

Motivated by recent experimental observations [Rowley et al. in Phys Rev 96:020407, 2017] on hexagonal ferrites, we revisit the phase diagrams of diluted magnets close to the lattice percolation threshold. We perform large-scale Monte Carlo simulations of XY and Heisenberg models on both simple cubic lattices and lattices representing the crystal structure of the hexagonal ferrites. Close to the percolation threshold p_c, we find that the magnetic ordering temperature T_c depends on the dilution p via the power law T_c ∼|p - p_c|^Φ with exponent Φ = 1.09, in agreement with classical percolation theory. However, this asymptotic critical region is very narrow, |p - p_c| ≲ 0.04. Outside of it, the shape of the phase boundary is well described, over a wide range of dilutions, by a nonuniversal power law with an exponent somewhat below unity. Nonetheless, the percolation scenario does not reproduce the experimentally observed relation T_c ~ (x_c -x)^2/3 in PbFe_12-xGa_xO₁₉. We discuss the generality of our findings as well as implications for the physics of diluted hexagonal ferrites.

Recommended Citation

G. Khairnar et al., "Phase Boundary Near a Magnetic Percolation Transition," The European Physical Journal B, vol. 94, Springer, Feb 2021.

The definitive version is available at https://doi.org/10.1140/epjb/s10051-021-00056-4

Department(s)

Physics

Research Center/Lab(s)

Center for High Performance Computing Research

Comments

The authors acknowledge support from the NSF under Grant nos. DMR-1506152, DMR-1828489, and OAC-1919789.

International Standard Serial Number (ISSN)

1434-6028; 1434-6036

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2021 Springer, All rights reserved.

Publication Date

02 Feb 2021