Magnetic, magneto-optic, and magneto-transport studies of thin film media of magneto-optical recording.
Committee ChairMansuripur, Masud
McIntyre, Laurence C.
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PublisherThe University of Arizona.
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AbstractThis dissertation contains a fairly comprehensive study on the characteristics of magneto-optical (MO) recording media. The primary aspects which are investigated consist of magnetic, magneto-optic, magneto-transport properties, and observations of domains. The main materials which have been examined are amorphous rare earth-transition metal (RE-TM) Tbₓ(FeCo)₁₋ₓ and multilayered Co/Pt and Co/Pd thin films. The samples were fabricated in several industrial and academic laboratories under different deposition conditions and deposited on different underlayers and substrates. The instrumentation used in this study include: a Vibrating Sample Magnetometer (VSM), a polar Kerr effect and extraordinary Hall effect loop tracer, an optical magnetic domain analyzer, and the magnetoresistance/resistivity probes. The magneto-optical property studied here is polar Kerr rotation. The magnetic properties investigated include saturation magnetization, coercivity, anisotropy energy constant, anisotropy field, and exchange coupling constant. The magneto-transport properties include resistivity, magnetoresistance and extraordinary Hall effect with four different geometries. In the domain observations, the domain nucleation, growth and collapse phenomena were investigated. In addition, the degree of jaggedness of various domain structures has been characterized by measuring the fractal dimension. Moreover, the domain distribution is analyzed in the demagnetized state both for the sample demagnetized by an in-plane magnetic field and the sample demagnetized by a perpendicular field. At the same time, both states were also studied in light of the initial magnetization curves obtained by measurements of polar Kerr effect, extraordinary Hall effect, and magnetoresistance. The domain density as a function of domain size as well as the minimum domain size can be inferred from the initial magnetization curves.