A Study of Magnetic Properties of Some Iron Compounds and Iron Tungsten Alloys

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Shamboul, Abdullahi El Balal
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University of Khartoum
In this thesis a general review of the theories that explain the magnetic properties of materials is presented. The classical treatment is briefly outlined followed by a quantum mechanical approach based on the Heisenberg exchange interaction and spin wave excitations. The experimental methods for magnetic measurements at various temperatures and magnetic fields are described. The magnetization measurements made at low temperature of some Iron-Tungsten alloys are then presented. The results give an' exchange constant which did not vary appreciably with the low concentration of tungsten. The investigation of the magnetization of Fe3P is given in detail. It is found that the magnetization vector lies in the basal plane of the tetragonal crystal and the saturation moments is 1.84µB per iron atom. An explanation of the low field magnetization along the c-axis and the spin structure is offered. The anisotropy energy constants are also determined. A brief study of Fe2P is made. It is found that the easy direction of magnetization is a1ong the c-axis of the hexagonal Crystal. The saturation magnetization found to be 114 e.m.u. per gram, giving a magnet on number of 1.46 µB per iron atom. The paramagnetic Curie temperature is 326 K and the effective magnet on number is 2.64 per iron atom. It is also found that the ferromagnetic Curie temperature is K…. in agreement with some results recently reported
Iron Tungsten Alloys, Magnetic Properties