Spin dynamics in Fe2 O3 -Te O2 glass: Experimental evidence for an amorphous oxide spin glass

We have examined spin dynamics including magnetic aging and memory effects as well as critical slowing down for 20 Fe2 O3·80Te O2 (mol %) glass. Scaling analysis on critical slowing down reveals that the present glass exhibits a critical behavior as observed in a prototype of spin glasses. Aging and memory effects peculiar to spin glasses have been observed in the magnetically ordered phase of the present glass. These experimental results strongly confirm that the 20 Fe2 O3·80Te O2 glass is converted into a spin glass phase at a very low temperature. It is thought that a disordered structure of the oxide glass gives rise to randomness and frustration in the magnetic structure, leading to the spin glass phase transition.