Eur. Phys. J. B 44, 439-445 (2005)
https://doi.org/10.1140/epjb/e2005-00143-2

The antiferromagnetic/paramagnetic transition in mixed-spin compounds R₂BaNiO₅

¹ Department of Physics, University of Michigan, Ann Arbor 48109, MI, USA
² Institut für Theoretische Physik J.W.G-Universität Frankfurt, Robert-Mayer-Str. 8 60054 Frankfurt am Main, Germany

Corresponding author: ^a jvalvare@umich.edu

Received: 27 July 2004
Revised: 18 October 2004
Published online: 30 May 2005

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.