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We have investigated the microwave oscillations due to a spin transfer effect induced by direct current in ferromagnetic nanocontact magnetoresistive (NCMR) elements with a current-perpendicular-to-plane spin-valve structure consisting of an FeCo/FeCo–AlOx nano-oxide layer/FeCo multilayer for the reference/spacer/free layers, respectively. Characteristic microwave oscillations were observed in the NCMR elements at different magnetization states induced by the application of a spin-polarized current, which are considered to be related to the introduction of a ferromagnetic NC to spacer layer (large interlayer coupling) and the resonance concerning the stability of the magnetization states of the free and reference layers around the NCs. A marvelously narrow full width at half maximum (FWHM) of l0–20 MHz is observed under a high applied magnetic field where the reference layer magnetization is slightly off axis relative to the pinned direction. By contrast, a wider FWHM of 80–600 MHz is observed at the magnetization state where the magnetization of the free layer just aligned to the antiparallel configuration against the magnetization of the reference layer. These characteristic results are discussed in terms of a spin dynamics mechanism induced by spin transfer torque in the free and reference layers around NCs. [ABSTRACT FROM AUTHOR]

In this study, we fabricated a Cr2O3 (0001) film without and with a Pt buffer layer and investigated its effect on perpendicular exchange coupling in a Cr2O3/Co3Pt interface. The results showed that the exchange bias field (μ0Hex) and blocking temperature (TB) of a Cr2O3 film without and with Pt were very different. The Cr2O3 film without Pt had a lower μ0Hex of 176 Oe and a lower TB of 75 K, whereas that with Pt had a higher μ0Hex of 436 Oe and a higher TB of 150 K. We discussed this difference in μ0Hex and TB values based on collinear/non-collinear coupling in a ferromagnetic and antiferromagnetic interface using Meiklejohn and Bean's exchange anisotropy model. [ABSTRACT FROM AUTHOR]

The bulk and interface spin scattering asymmetric coefficients, βF and γF/N, respectively, as well as the interfacial specific resistance, AR*F/N, contribute to the total resistance change-area product, ΔRA, in current-perpendicular-to-plane (CPP) geometry. In this paper, we report the effect of the insertion of a 1 nm Fe layer into ferromagnetic (F)/non-ferromagnetic (N) interfaces on the spin dependent transport properties. Using the Valet-Fert theory based on the two-current model in which ΔRA is obtained as a function of thicknesses of the ferromagnetic layer (3, 4, and 5 nm), we experimentally deduced the values of βF, γF/N, and AR*F/N of exchange-biased spin valves (EBSVs) for an artificially ordered B2 state Fe50Co50 alloy as a magnetic layer and an Ag spacer layer. [ABSTRACT FROM AUTHOR]