Determination of the exchange energies in Li2VOSiO4 from a high-temperature series analysis of the square lattice J1-J2 Heisenberg model

TL;DR

This paper uses high-temperature series analysis to determine the exchange energies in Li2VOSiO4, successfully modeling its magnetic properties with the J1-J2 Heisenberg model on a square lattice.

Contribution

It introduces an improved high-temperature expansion method to accurately extract exchange energies from experimental susceptibility and specific heat data.

Findings

Exchange energies J1 and J2 are estimated as 1.25±0.5 K and 5.95±0.2 K.

The model reproduces the experimental data very well.

Maximum of specific heat is related to J2/J1 ratio.

Abstract

We present a high-temperature expansion (HTE) of the magnetic susceptibility and specific heat data of Melzi et al. on Li2VOSiO4 [Phys. Rev. B 64, 024409 (2001)]. The data are very well reproduced by the J1-J2 Heisenberg model on the square lattice with exchange energies J1=1.25+-0.5 K and J2=5.95+-0.2 K. The maximum of the specific heat Cv^{max}(T_{max}) is obtained as a function J2/J1 from an improved method based on HTE.