Exact solution of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chain

TL;DR

This paper provides an exact analytical study of the ground state, magnetization, and specific heat in a geometrically frustrated mixed spin-1/2 and spin-S Ising-Heisenberg diamond chain, revealing how spin value and frustration influence magnetic properties.

Contribution

It introduces a combination of three exact methods to analyze the frustrated diamond chain, highlighting the effects of spin magnitude and frustration on magnetization and magnetocaloric behavior.

Findings

Increase in spin S leads to more magnetization plateaux.

All plateaux merge into a linear curve as S approaches infinity.

Enhanced magnetocaloric effect observed in frustrated ground states.

Abstract

The geometric frustration in a class of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chains is investigated by combining three exact analytical techniques: Kambe projection method, decoration-iteration transformation and transfer-matrix method. The ground state, the magnetization process and the specific heat as a function of the external magnetic field are particularly examined for different strengths of the geometric frustration. It is shown that the increase of the Heisenberg spin value S raises the number of intermediate magnetization plateaux, which emerge in magnetization curves provided that the ground state is highly degenerate on behalf of a sufficiently strong geometric frustration. On the other hand, all intermediate magnetization plateaux merge into a linear magnetization versus magnetic field dependence in the limit of classical Heisenberg spin S -> infinity. The enhanced magnetocaloric effect with cooling rate exceeding the one of paramagnetic salts is also detected when the disordered frustrated phase constitutes the ground state and the external magnetic field is small enough.