Examining Magnetic Models and Anisotropies in beta-Cu2V2O7 by High-Frequency ESR

摘要

High-frequency electron spin resonance (ESR) measurements were carried out on a single crystal beta-Cu2V2O7, where Cu-O edge-sharing chains are connected by non-magnetic VO4 tetrahedrons. Due to sizable anisotropies, analyses of bulk magnetic properties alone have not yielded any definite conclusion and the modeling of the magnetic lattice is controversial. By means of high-frequency ESR with operating frequencies of 135-405 GHz and at a temperature range of 4.2-50 K, the large g value anisotropy is determined, which removes the ambiguity of susceptibility fitting. Moreover, non-negligible exchange anisotropy is evaluated by analyzing high-field magnetization and antiferromagnetic resonance in antiferromagnetic state appearing below T (N) = 26 K. Based on these microscopic information, we found that alternating-chain model is the most reasonable candidate for explaining properties of the crystal. The present study shows the importance of combining macroscopic and microscopic probes in analyzing magnetic network of complex magnetic materials.