Enhanced magnetocaloric effect in a proximity of magnetization steps and jumps of spin-1/2 XXZ Heisenberg regular polyhedra

TL;DR

This study investigates the magnetization and magnetocaloric properties of spin-1/2 XXZ Heisenberg polyhedral clusters, revealing the role of quantum interactions in creating magnetization steps and an enhanced magnetocaloric effect.

Contribution

It demonstrates the impact of quantum (xy) interactions on magnetization steps and the magnetocaloric effect in polyhedral clusters, extending understanding beyond the Ising limit.

Findings

Presence of intermediate magnetization plateaux due to quantum interactions

Enhanced magnetocaloric effect near magnetization steps

Quantitative shift of level-crossing fields in the tetrahedron

Abstract

The magnetization process and adiabatic demagnetization of the antiferromagnetic spin-1/2 XXZ Heisenberg clusters with the shape of regular polyhedra (tetrahedron, octahedron, cube, icosahedron and dodecahedron) are examined using the exact diagonalization method. It is demonstrated that a quantum (xy) part of the XXZ exchange interaction is a primary cause for presence of additional intermediate magnetization plateaux and steps, which are totally absent in the limiting Ising case. The only exception to this rule is the spin-1/2 XXZ Heisenberg tetrahedron, which shows just a quantitative shift of the level-crossing fields related to two magnetization steps. It is evidenced that the spin-1/2 XXZ Heisenberg regular polyhedra exhibit an enhanced magnetocaloric effect in a proximity of the magnetization steps and jumps, which are accompanied with a rapid drop (rise) of temperature just above (below) of the level-crossing field when the magnetic field is removed adiabatically.