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We investigate the microwave response of a spin transfer vortex based oscillator in a magnetic tunnel junction with an in-plane reference layer combined with a spin valve with an out-of-plane magnetization spin polarizing layer. The main advantage of this perpendicular spin polarizer is to induce a large spin transfer force even at zero magnetic field, thus leading to a record emitted power (up to 0.6 μW) associated to a very narrow spectral linewidth of a few hundreds of kHz. The characteristics of this hybrid vortex based spin transfer nano-oscillator obtained at zero field and room temperature are of great importance for applications based on rf spintronic devices as integrated and tunable microwave source and/or microwave detector. [ABSTRACT FROM AUTHOR]

We have studied the magnetic properties at room temperature of Fe1-xGax (FeGa) epitaxial thin films grown on ZnSe/GaAs(100) for 0.14≤x≤0.29 range concentration, and film thicknesses, d = 36 and 72 nm. The study was performed by means of magnetometric measurements and magnetic force microscopy scans. Increasing x promotes the loss of the four-fold magnetic-crystalline anisotropy associated to an Fe-like behavior, which is lost completely above x = 0.20. Stripe domains with rotatable anisotropy are observed even in samples in which the theoretical conditions for stripe appearance are not completely fulfilled. An unexpected 'saw-tooth' stripe structure has been found under certain conditions. [ABSTRACT FROM AUTHOR]

We investigated the electronic properties of MnAs nano-clusters embedded in GaAs by bulk sensitive photoemission spectroscopy and cross-sectional scanning tunneling microscopy/spectroscopy. We report experimental evidences that the clusters are metallic MnAs, in close resemblance to MnAs thin films, and display a sharp interface with the surrounding GaAs. These results are supported by the comparison with GaMnAs and MnAs film in the same experimental condition. Furthermore, we observe a clear Coulomb blockade effect, as due to confinement and their nanometric size. [ABSTRACT FROM AUTHOR]

We determined the magnetic anisotropy energy and g-factor of an uncapped 10 nm thick Fe/GaAs(110) film using a setup that allows frequency (1.5-26.5 GHz) as well as angular dependent ferromagnetic resonance measurements under ultrahigh vacuum conditions. The g-factor g=2.61±0.1 is unusually high at room temperature and can be interpreted as the result of an increased orbital moment due to strain. This interpretation is supported by more surface sensitive x-ray magnetic circular dichroism measurements which yield g=2.21±0.02 measured at remanence. The difference in g may be the result of magnetic field dependent magnetostriction which influences the orbital moment. [ABSTRACT FROM AUTHOR]

We investigate the magnetic domain structure and stray field of MnAs/GaAs(001) thin films by magnetic force microscopy of the growth surface and of cleavage edges. The strong uniaxial magnetic anisotropy of MnAs makes the magnetic properties very similar to those of a rectangular bar magnet with constant magnetization along the easy axis direction. By analytical calculations we estimate the out-of-plane magnetic stray field component acting on electrons injected by a MnAs contact into a GaAs-based device. [ABSTRACT FROM AUTHOR]