High-field ESR study of kagome-like substance Cu 3V 2O 7(OH) 2·2H 2O

Abstract

As Cu 2+ ions in Cu 3V 2O 7(OH) 2·2H 2O form two-dimensional deformed kagome lattice structure in the ab plane, frustration is expected. To clarify the magnetic properties of this system, we performed X-band ESR measurement and high-field ESR measurements up to 16 T. The ESR signal disappeared below 5 K in X-band ESR measurement and the ESR absorption line showed clear shift below 4.2 K in our high-field ESR measurement at 80 GHz. Although no long-range order is expected around 4 K from the result of the specific heat measurement, our frequency-dependent measurement at 1.8 K showed the existence of the internal field in Cu 3V 2O 7(OH) 2·2H 2O. The results of the temperature dependences of the resonance field and the linewidth are also presented and discussed in connection with other kagome substances.