Evidence of the spin glass state in (Bi1.88Fe0.12)(Fe1.42Te0.58)O6.87 pyrochlore

The (Bi1.88Fe0.12)(Fe1.42Te0.58)O6.87 pyrochlore with very high Fe content undergoes a transition to the spin glass state at its glass temperature Tg∼21 K. The spin glass state in this compound has been evidenced by demonstrating the so-called “memory effect” in the zero-field-cooled magnetization. The memory effect is clearly observed at temperatures below Tg and no such effect can be observed above Tg. Further, the “rejuvenation” effect, has clearly been observed, which evidences the chaotic nature of the spin glass state. A possible origin of such glassy state is discussed.