| Microelectronics features studying and controlling the charges and transport properties of electrons, and is the basis of modern information technology. In conventional microelectronics, however, the spin of electron, which was simply seen as a carrier of charges, barely caught attentions. With the increasing integration level, the scale of semiconductor devices has entered nanometer, causing dramatic increase in energy consumption in unit area, and severe heat loss, and subsequently, poor performance and stability. In the late 80s, Fert and Grunberg discovered the Giant Magneto-Resistance almost simultaneously, which lead to a revolution in magnetic storage and record, giving a decisive push to the take-off of massive application of computers in the 1990s. From then on, spintronics, a new branch which studies, utilizes and control the electron transport of spin polarization, has become the hotspot of science community. The goal of spintronics is to realize modulation of electron transport properties and develop new electronic devices. To fulfill that goal, the prerequisite task is developing a new material with both the band gap of semiconductor, as well as the sub-band splitting of magnetic material. Therefore, the preparation of ferromagnetic semiconductor with room temperature magnetism and high spin polarization is important.The preparation method of typical ferromagnetic semiconductor is to dope transition element into the current semiconductor system. It is expected that the transition element may enter the crystal lattice by substituting some cations'positions, and through ferromagnetic coupling between transition metal ions, ferromagnetism may appear in semiconductor on the basis of the original band-gap. In 1990s, Ohno et. al. successfully doped Mn element into GaAs. The Curie temperature, however, is 170K, which does not meet the requirements of application. In the year of 2000, based on the traditional Zener model, T. Dietl et. al. calculated and predicted a Curie temperature of higher than 300K in Mn doped wide band-gap semiconductors such as GaN and ZnO. After this report, the research enthusiasm toward oxide-based ferromagnetic semiconductor has been immediately aroused and a lot of experimental and theoretical works have been evolved. The most studied systems are ZnO and TiO2. However, results reported by different groups are different or even contradictory. To date, the question whether intrinsic ferromagnetism exists in transitional element doped oxide systems is still inconclusive. Meanwhile, although the research on In2O3-based ferromagnetic semiconductor is still in its early stage, many groups have reported the existence of ferromagnetism, and some has even revealed unique properties such as anomalous Hall effect and a solubility as high as 20% of iron in In2O3. Based on such a background, also with a view to the excellent opto-electric and gas sensitive properties of InO3, we finally choose Fe-doped In2O3 as the study system of this thesis, and try to solve the questions below: whether high temperature intrinsic ferromagnetism can be realized in iron doped indium oxide and what is the origin of ferromagnetism.Pulsed laser deposition is used for sample preparation and the ceramic targets are sintered using solid state reaction method. In this work, We have grown single crystalline Fe-doped In2O3 film on YSZ substrate. XRD indicates the sample has a preferential growth direction along (100),(110) and (111) directions, without any secondary phases such as iron, iron oxides and other indium-iron compounds. Magnetic measurements indicate a strong magnetic anisotropy with the easy axis perpendicular to the film surface. AFM measurement shows a columnar growth mode perpendicular to the substrate. AHE(Anomalous Hall Effect) measurements show a distinctive hysterisis loop, which is widely considered as an evidence to intrinsic ferromagnetism in DMSs.In brief, studies in this thesis have achieved such results:Fe-doped In2O3 films grown along all three chosen crystal directions were successfully prepared by PLD. Strong perpendicular magnetic anisotropy is realized. XRD measurements show films on three directions have excellent eptaxial structure, and AHE measurements indicate a room-temperature Anomalous Hall Effect, which further proves the intrinsic ferromagnetism, with ideal crystal structure.
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