Ferromagnetic oxides

Ferrite. Iron which, in pig iron or steel, has not combined with carbon to form cementite (FeaC). It exists in a, /9, y and 8 forms, which vary in magnetism and ahility to dissolve cementite. Name also applied to compd NaFe02 (called Na ferrite), to ferromagnetic oxides having a definite cryst structure (spinels) and the formula M++Fe ++04 of which the divalent metal may be Fe, Ni, Zn, or Mn. The magnetic props vary accdg to the divalent atom present, and ferrites are now tailored for their desired effect, as Ni-Al ferrite ... 

Smit, J. and Wijn, H.P.J. (1959) Ferrites - physical properties of ferromagnetic oxides in relation to their technical applications, Philips Technical Library, The Netherlands. 

R642 K. Asai, Studies of Ferromagnetic Oxides with Ordered Double Perovskite Structure by Nuclear Probes , KURRI-KR, 2000, (KURRI-KR-49, Proceedings of the Specialist Research Meeting on New Developments in Solid State Physics with Probes of Radiations and Nuclei, 1999), 229... 

It will, of course, be understood that this explanation of thermal deactivation is by no means the only deactivation process which can occur. Morris and Selwood found that nickel supported on magnesia could be thermally deactivated with no recession of the Curie point. Nevertheless, the method seems to be a powerful one, which might be applied to other ferromagnetic metals, and to ferromagnetic oxides and ferrites such as copper ferrite undergoing isomorphous replacement of copper by zinc, as described by Snoek (44). 

Lotgering, F.K. (1959) Topotactical reactions with ferromagnetic oxides having hexagonal crystal structures - I. 

J.M.D. Coey, M. Venkatesan, C.B. Fitzgerald, Donor impurity band exchange in dilute ferromagnetic oxides. Nat. Mater. 4(2), 173-179 (2005)... 

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