Glassy magnetic behavior induced byCu2+ substitution in the frustrated antiferromagnetZnCr2O4

Abstract

The structure and magnetic properties of the compoundsZn1−xCuxCr2O4 (ZCCO) are investigated systematically. A structural phase transition from space-group symmetryFd3m to I41/amd is observed in ZCCO. The critical value of the doping,x, appears at 0.58–0.62 through the appearance of a splitting of diffraction peaksat room temperature. Measurements of dc magnetization, ac susceptibility,memory effect and exchange-bias-like (EB-like) effect have been performedto reveal the glassy magnetic behaviors of ZCCO. The system withx≤0.50 suggests a spin glass-like (SG-like) magnetic characterization whereas doping values of0.58≤x≤0.90 define the system as ‘cluster-glass-like’ (CG-like) with unidirectionalanisotropy. The Cu content suppresses the geometrical frustration ofZnCr2O4, which may correlate with the pinning effect of the Cu sublattice on the Cr sublattice to apreferential direction.