Chemistry

Magnetic properties of a quantum spin ladder in proximity to the isotropic limit

S. A. Zvyagin, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
A. N. Ponomaryov, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
M. Ozerov, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
E. Schulze, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
Y. Skourski, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
R. Beyer, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
T. Reimann, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
L. I. Zviagina, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
E. L. Green, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
J. Wosnitza, HZDR - Helmholtz-Zentrum Dresden-Rossendorf
I. Sheikin, Laboratoire National des Champs Magnétiques Intenses (LNCMI)
P. Bouillot, Université de Genève
T. Giamarchi, Université de Genève
J. L. Wikara, University of Canterbury
M. M. Turnbull, Clark University
C. P. Landee, Clark University

Abstract

We report on the synthesis, crystal structure, magnetic, thermodynamic, and electron-spin-resonance properties of the coordination complex [Cu2(pz)3(4-HOpy)4](ClO4)4 (pz=pyrazine; 4-HOpy=4-hydroxypyridine). This material is identified as a spin-1/2 Heisenberg ladder system with exchange-coupling parameters Jrung/kB=12.1(1)K and Jleg/kB=10.5(3)K [Jrung/Jleg=1.15(4)]. For single crystals our measurements revealed two critical fields, μ0Hc1=4.63(5)T and μ0Hc2=22.78(5)T (for H∥a∗), separating the gapped spin-liquid, gapless Tomonaga-Luttinger-liquid, and fully spin-polarized phase. No signature of a field-induced transition into a magnetically ordered phase was found at temperatures down to 450 mK. The material bridges an important gap by providing an excellent physical realization of an almost isotropic spin-1/2 strong-rung Heisenberg ladder system with modest exchange-coupling energy and critical-field scales.