Cluster spin glass behavior in geometrically frustrated Zn3V3O8

We report the bulk magnetic properties of a yet unexplored vanadium-based multi-valenced spinel system, Zn3V3O8. A Curie-Weiss fit of our dc magnetic susceptibility chi(T) data in the temperature region of 140-300 K yields a Curie constant C = 0.75 cm(3) K mole(-1) V-1, theta(CW) = -370 K. We have observed a splitting between the zero field cooled (ZFC) and field cooled (FC) susceptibility curves below a temperature T-irr of about 6.3 K. The value of the 'frustration parameter' (vertical bar theta(CW)vertical bar/T-N similar to 100) suggests that the system is strongly frustrated. From the ac susceptibility measurements we find a logarithmic variation of freezing temperature (T-f) with frequency nu attesting to the formation of a spin glass below T-f. However, the value of the characteristic frequency obtained from the Vogel-Fulcher fit suggests that the ground state is closer to a cluster glass rather than a conventional spin glass. We explored further consequences of the spin glass behavior and observed aging phenomena and memory effect (both in ZFC and FC). We found that a positive temperature cycle erases the memory, as predicted by the hierarchical model. From the heat capacity C-P data, a hump-like anomaly was observed in C-P/T at about 3.75 K. Below this temperature the magnetic heat capacity shows a nearly linear dependence with T which is consistent with the formation of a spin glass state below T-f in Zn3V3O8.