Studies Of Magnetic Properties On Magnetite Thin Film

In the last thirty years, people dreamed to combine magnetic device withsemiconductor technique and to form the new field of magnetoelectronics with thedevelopment of solid electronics and the maturation of techniques of semiconductorand IC industry. So studies on the growth and properties of magnetic thin film onsemiconductor substrate has become key fundamental research for the integrate newelectronics device. In this thesis, by using experimental methods such as FMR,magnetic and electrics measurement, systematical studies have been made ontransport, magnetic anisotropy, magnetic moment and damping coefficient of epitaxialsingle crystalline Fe₃O₄ films on GaAs. The major results are summarized asfollowing:1. Monitored by RHEED, the epitaxial Fe₃O₄ thin film is synthesized by in-situpost annealing at the temperature of 500 K and the oxygen pressure of 5×10-5 mbarafter growing Fe thin film on GaAs substrate. The quality of the thin film prepared inthis method has also been analyzed by X-ray diffraction. The result confirms that theFe₃O₄ thin film is the well defined cubic single crystalline.2. The magnetic properties of the Fe₃O₄ have been measured by VSM. With thethickness increasing, the VSM measurement revealed the evolution fromsuperparamagnetism to ferromagnetism. The magnetic anisotropy showed the processfrom the dominant uniaxial anisotropy and accompanying cubic anisotropy tobasically cubic symmetrical anisotropy. The easy and hard axis was also changed.3. We investigated the resistance using measurements of the resistivity as afunction of temperature. We also made simulation with Boltzman function anddetermined the activation energy at the temperature range from 150 K to 300 K.4. FMR linewidth studies were performed on single crystalline Fe ultra thin filmsepitaxially grown on III-V semiconductor GaAs substrate (100) with differentthickness. In order to fit the experimental angular dependence of FMR linewidth anexpression of anisotropic damping coefficient is proposed. In fitting with the...