Document Type

Article

Publication Date

8-5-2002

Journal or Book Title

Physical Review B

Volume

66

First Page

054407

DOI

10.1103/PhysRevB.66.054407

Abstract

We report the results of systematic experimental and theoretical studies of two closely related species of magnetic molecules of the type {V6}, where each molecule includes a pair of triangles of exchange-coupled vanadyl (VO2+,spin s=1/2) ions. The experimental studies include the temperature dependence of the low-field susceptibility from room temperature down to 2 K, the dependence of the magnetization on magnetic field up to 60 T for several low temperatures, the temperature dependence of the magnetic contribution to the specific heat, and the 1H and 23Nanuclear magnetic resonance spin-lattice relaxation rates 1/T1. This body of experimental data is accurately reproduced for both compounds by a Heisenberg model for two identical uncoupled triangles of spins; in each triangle, the spins interact via isotropic antiferromagnetic exchange, where two of the three V-V interactions have exchange constants that are equal and an order of magnitude larger than the third; the ground-state eigenfunction has total spin quantum number S=1/2 for magnetic fields below a predicted critical field Hc≈74T and S=3/2 for fields above Hc.

Comments

This article is from Physical Review B 66 (2002): 054407, doi:10.1103/PhysRevB.66.054407. Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

Share

COinS