HOPKINSON EFFECT STUDY IN SPINEL AND HEXAGONAL FERRITES

Jozef Sláma – Martin Šoka – Anna Grusková – Alvaro Gonzales – Vladimír Jančárik

   The magnetic susceptibility shows a Hopkinson peak just below the Curie temperature T_C when heating the selected hexagonal and spinel ferrite samples. It is proposed that this peak can be associated with a transition from stable magnetic state to super-paramagnetic relaxation above the blocking temperature up to the T_C. The Hopkinson effect results are compared with SEM micrographs of both studied hexagonal and spinel ferrites.

Keywords: Hopkinson effect, super-paramagnetic relaxation, blocking temperature, spinel and hexagonal ferrite

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