Observation of weak ferromagnetism and the sizable magnetocaloric effect in Co2V2O7

Abstract The magnetic behavior of cobalt pyrovanadate compound Co 2 V 2 O 7 with dichromate structure is reported. The compound undergoes long range magnetic ordering below T C =8 K and our study identifies the ground state to be a canted antiferromagnetic type with a weak ferromagnetic component. The transition at T C is found to be first-order in nature as evident from the presence of distinct thermal hysteresis in the temperature dependent magnetization data. Below T C , a significantly large value of magnetic relaxation is observed which is possibly due to the metastability associated with the first order phase transition. Interestingly, the sample exhibits a sizable magneto-caloric effect around T C (∼4.1 J kg −1 . K −1 for 50 kOe of field change) which is reasonably high among antiferromagnetic transition metal oxides with weak ferromagnetism.