The antiferromagnetic/paramagnetic transition in mixed-spin compounds R2BaNiO5

TL;DR

This study uses Quantum Monte Carlo simulations to analyze the magnetic properties of R2BaNiO5 compounds, revealing the coexistence of long-range order and quantum gap excitations, and emphasizing the role of quantum fluctuations.

Contribution

The paper provides a detailed quantum Monte Carlo analysis of R2BaNiO5, highlighting quantum fluctuations' importance, which were neglected in earlier mean-field approaches.

Findings

Excellent agreement with experimental data

Coexistence of 3D magnetic order and 1D quantum gaps

Quantum fluctuations are crucial for accurate modeling

Abstract

We present an extensive Quantum Monte Carlo study of the magnetic properties of the mixed-spin quantum systems R2BaNiO5 (R= magnetic rare earth) which show coexistence of 3-dimensional magnetic long-range order with 1-dimensional quantum gap excitations. We discuss the validity of the performed simulations in the critical region and show the excellent agreement with experimental results. We emphasize the importance of quantum fluctuations contained in our study which is absent in previous mean-field-like treatments.