METAMAGNETISM IN MnMg FERRITE: MEDIUM FOR MAGNETIC CLOAK AND SHIELDING

Jozef Sláma – Martin Šoka – Vladimír Jančárik

   The metamagnetic transition (MT) from anti-ferromagnetic (AFM) to ferrimagnetic (FM) state by applying a magnetic field was studied in the Fe-deficient MgMn ferrite. It is presented that MgMn ferrite shows MT at temperature variations under ap-plied field below the critical value of field strength H_t. The critical transition field H_t = 580 A/m was estimated for MT from the AFM to FM state from temperature dependence of remanent magnetic flux density. It is assumed, that the MT can be induced by changes of the anisotropy. In the studied magnetic system, the AFM state changes to FM state under the influence of magnet-ic field at adequate transition temperature T_t. One class of the MgMn ferrites that can become attractive are the metamagnetic systems. On base of studied ferrite can be constructed a cloak that can shield an object from a dc and/or ac magnetic field.

Keywords: metamagnetism, MnMg ferrite, magnetic cloak

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