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The magnetic and structural properties of Fe films deposited by ion-beam sputtering (IBS) on (100)-oriented GaAs substrates are described. The films are between 30 and 600 nm thick and are characterized by a coercive field of approximately 3–6 Oe. The saturation magnetization and anisotropy field, inferred from vibrating sample magnetometer measurements agree substantially with the values expected for bulk Fe. Films deposited on the (100) substrate show the expected fourfold (or ‘‘biaxial’’) symmetry with no indication of a uniaxial anisotropy component. These properties make the films ideally suitable for the intended application in a hybrid semiconductor-magnetic memory, in which two magnetic remanent states with mutually orthogonal magnetization directions interact with an electronic flip-flop circuit.

Unusual metallic behavior in nanostructured cobalt ferrite at superparamagnetic regime J. Appl. Phys. 112, 063926 (2012) Investigation of structural, dielectric, and magnetic properties of hard and soft mixed ferrite composites J. Appl. Phys. 112, 054323 (2012) Magneto-optical study of holmium iron garnet Ho3Fe5O12 Low Temp. Phys. 38, 863 (2012) Growth and ferromagnetic resonance of yttrium iron garnet thin films on metalsThe ferromagnetic resonance ͑FMR͒ linewidth, the field dependent effective linewidth, and the parallel pump spin wave linewidth were measured for spheres and disks prepared from a block of hot isostatic pressed ͑hipped͒ polycrystalline yttrium iron garnet ͑YIG͒. All linewidths as well as static magnetization data indicate close to 100% density. Vibrating sample magnetometer measurements give an average saturation induction 4M s of 1825 G. The FMR half-power linewidths for the spheres at 9.5 GHz were 13 Oe. Linewidths measured over the 9.5-18 GHz frequency range show a small but distinct drop and agree with Schlömann's theory of anisotropy-dominated two-magnon scattering for polycrystalline ferrites. The effective linewidth versus field data at 10 GHz show a region of strong absorption that corresponds to the width of the spin wave manifold for low wave numbers and a high field value of about 2 Oe. Parallel pumping measurements give minimum spin wave linewidths of 1.2 and 0.6 Oe at 9 and 16.7 GHz, respectively. The 16.7 GHz spin wave linewidths correspond to half-frequency spin waves at 8.35 GHz. The extrapolated linewidths at zero wave number are about 0.5 Oe and match the established intrinsic linewidths expected for YIG single crystals at 8 -9 GHz. The spin wave linewidths increase linearly with wave number and are consistent with a transit time scattering process with scattering lengths that are about ten times greater than the average grain size.

Highly anisotropic SmCo based films with the TbCu7-type structure have been sputter deposited directly onto YIG substrates. The SmCo crystallites have the c axes approximately randomly splayed about the substrate plane such that the easy direction of magnetization of the SmCo film is in the film plane. The in-plane static energy product of the SmCo film layers was about 16 MG Oe. In-plane vibrating sample magnetometer hysteresis loops of the SmCo film and YIG substrate exhibit a composite form with the YIG field reversal shifted into the first quadrant by the looping field from the SmCo film layer. Approximately 4×4 mm2 pieces of YIG substrate have been measured to determine the YIG bias field and field required for reverse saturation of the YIG as a function of the SmCo based film layer thickness to YIG substrate thickness. It is observed that for SmCo to YIG thickness ratios greater than 0.22, the looping field from the SmCo film layer is sufficient to saturate the YIG magnetization in the reverse direction. SmCo film thicknesses in the range from 80 to 120 μm have been used in these studies. Special boundary layers have been used to promote thick film adhesion to the YIG substrates.

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