Spin disorder induced reentrant ferromagnetism in iron-based nanocomposites |
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Authors: | S Mukherjee S Kumar D Das |
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Institution: | (1) Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi, 835215, Jharkhand, India;(2) Department of Physics, Jadavpur University, Kolkata, 700032, India;(3) UGC DAE CSR, Kolkata Centre III/LB 8, Bidhannagar, Kolkata, 700098, India |
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Abstract: | The low-temperature magnetic behavior of pure iron nanocrystallites dispersed in MgO matrix has been investigated by dc magnetization
and ac susceptibility measurements. Irreversibilities in the magnetization data at low field are observed at low temperatures,
indicating a passage from a high temperature ferromagnetic phase to a low-temperature disordered, frozen state. Quenching
of these irreversibilities is seen when the external magnetic field is increased. The variation of the in-phase susceptibility
with temperature showed marked frequency dependence whereas the out-of-phase susceptibility component passes through a maximum.
The origin of this behavior is traced to the spin disorder at the grain boundaries, which exhibit a co-operative freezing
below a certain temperature. |
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Keywords: | |
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