Thermodynamics of the (1,1/2) Ferrimagnet in Finite Magnetic Fields

TL;DR

This paper studies the thermodynamic properties of a ferrimagnet with specific spin configuration under finite magnetic fields, revealing complex behaviors such as double peak specific heat and critical field-induced magnetization changes.

Contribution

It provides new insights into the thermodynamics of a (1,1/2) ferrimagnet in magnetic fields, combining numerical DMRG results with analytical understanding.

Findings

Double peak structure in specific heat.

Identification of two critical magnetic fields Hc1 and Hc2.

Square-root behavior of magnetization near critical fields.

Abstract

We investigate the specific heat and magnetisation of a ferrimagnet with gS=1 and S=1/2 spins in a finite magnetic field using the transfer matrix DMRG down to T=0.025J. Ferromagnetic gapless and antiferromagnetic gapped excitations for H=0 lead to rich thermodynamics for H > 0. While the specific heat is characterized by a generic double peak structure, magnetisation reveals two critical fields, Hc1=1.76(1) and Hc2=3.00(1) with square-root behaviour in the T=0 magnetisation. Simple analytical arguments allow to understand these experimentally accessible findings.