Specific heat of the Kagomé mixed compounds (Co 1−xNi x) 3V 2O 8

Abstract

We present high-resolution specific heat data from 2 to 30 K of the mixed Kagomé compounds (Co 1− x Ni x ) 3V 2O 8 for x=0, 0.12, 0.2, 0.5 and 1.0. We show that the specific heat at the first-order transitions of the end compounds ( x=0 and 1), obtained using relaxation calorimetry, is up to a factor of 10 larger than that previously reported in the literature. The mixed compounds exhibit only the highest temperature transition to an presumably, incommensurate magnetic structure. A slope change of T N versus x at x=0.2 indicates the transition from the Ni 3V 2O 8- to Co 3V 2O 8-type magnetic structures.