Role of defects on the magnetic behaviour of the geometrically frustrated spinel ZnFe2O4

摘要: Abstract Defective zinc ferrites ZnFe2O4-δ obtained by vacuum annealing bulk Zn-ferrite at different temperatures TAnn were investigated using XANES Zn-K, Fe-K and XMCD Fe-L2,3 edges, static dynamic magnetic measurements. The cation inversion that confers to the starting ferrite a weak ferromagnetic response is progressively lost when surpasses 250 °C. Consequently, there detriment of reaches its lower value for around 370 °C, being latter coincident with negligible non-equilibrium occupancy. Above 450 °C enhances response. In such case, even though Zn Fe occupy sites surface regions, deficiency oxygen predominates over former triggers an increment coupling between Fe3+ octahedral spinel sites. We discuss results account spin-glass and/or cluster-glass behavior this geometrically frustrated compound as due randomness frustration introduced local defects.