MAGNETIC PROPERTIES AND INTERPARTICLE MAGNETIC INTERACTIONS IN POWDER SAMPLES OF MAGNETITE AND MAGNESIUM OXIDE MIXTURES

In this paper, magnetic properties and interparticle magnetic interactions of the powder mixtures consisting of a ferromagnetic magnetite (mean particle size about 50 nm) and diamagnetic MgO (micrometric particles) are presented. Mixtures with concentrations of Fe3O4 from 10 to 80 wt. % were prepared using two methods: ultrasonic homogenization and manual mechanical mixing. Additionally the powder mixtures were mechanically pressed in a specially developed device to produce samples in form of pills with the diameter of 10 mm. An EV9 MicroSense vibrating sample magnetometer (VSM) was used for measurements of the virgin curves and magnetization loops. Both measured quantities were used for construction of the Henkel plots that indicate the behavior of the magnetic interparticle interactions of prepared samples. We have discovered that the sample with 30 wt. % of Fe3O4 exhibited the most intensive interparticle interactions and at the same time the highest value of the remnantand saturation magnetization.