W. Schoch

Scaling behavior of the spin pumping effect in ferromagnet-platinum bilayers.

We systematically measured the dc voltage V(ISH) induced by spin pumping together with the inverse spin Hall effect in ferromagnet-platinum bilayer films. In all our samples, comprising ferromagnetic 3d transition metals, Heusler compounds, ferrite spinel oxides, and magnetic semiconductors, V(ISH) invariably has the same polarity, and scales with the magnetization precession cone angle. These findings, together with the spin mixing conductance derived from the experimental data, quantitatively corroborate the present theoretical understanding of spin pumping in combination with the inverse spin Hall effect.

Magnetic property investigations on Mn-doped ZnO Layers on sapphire

The need for diluted magnetic semiconductors has stimulated research on Mn-doped ZnO. However, the type of magnetic coupling (ferro/para) in ZnMnO remains an issue of debate. We have investigated the magnetic properties of Mn-doped ZnO layers grown by molecular beam epitaxy. Some samples showed a hysteresis with remnant magnetization on the order of 10−5emu, thus eventually suggesting ferromagnetism. We observed that the critical influence of the substrate substantially affects magnetic property measurements. This has to be taken into account in order to clearly confirm ferromagnetism. In our case, after subtraction of the substrate effect, there is no evidence of a ferromagnetic behavior for the ZnMnO samples.

Spin wave resonance in Ga1−xMnxAs

We report ferromagnetic resonance experiments on Ga1−xMnxAs thin films. For the dc magnetic field perpendicular to the sample plane, we observe up to eight distinct resonances, which we attribute to spin wave modes. To account for the spacing of the resonances, we infer a linear gradient in the magnetic properties, which is ascribed to a linear variation of the uniaxial magnetic anisotropy with film thickness. Values of D=(1±0.4)×10−9 Oe cm2 for the spin stiffness and JMnMn≈1 meV for the exchange integral between Mn spins are obtained.

Ga1-xMnxAs/piezoelectric actuator hybrids : A model system for magnetoelastic magnetization manipulation

We have investigated the magnetic properties of a piezoelectric actuator/ferromagnetic semiconductor hybrid structure. Using a GaMnAs epilayer as the ferromagnetic semiconductor and applying the piezo-stress along its [110] direction, we quantify the magnetic anisotropy as a function of the voltage Vp applied to the piezoelectric actuator using anisotropic magnetoresistance techniques. We find that the easy axis of the strain-induced uniaxial magnetic anisotropy contribution can be inverted from the [110] to the [

Angle-dependent magnetotransport in cubic and tetragonal ferromagnets: Application to (001)- and "113…A-oriented "Ga,Mn…As

General expressions for the longitudinal and transverse resistivities of single-crystalline cubic and tetragonal ferromagnets are derived from a series expansion of the resistivity tensor with respect to the magnetization orientation. They are applied to strained

Curie temperature and carrier concentration gradients in epitaxy-grown Ga1−xMnxAs layers

(\mathrm{Ga},\mathrm{Mn})\mathrm{As}

Advanced resistivity model for arbitrary magnetization orientation applied to a series of compressive- to tensile-strained (Ga,Mn)As layers

films, grown on (001)- and

Passivation of Mn acceptors in GaMnAs

(113)A

Effect of annealing on the depth profile of hole concentration in (Ga,Mn)As

-oriented

Strain, magnetic anisotropy, and anisotropic magnetoresistance in (Ga,Mn)As on high-index substrates: Application to (113)A-oriented layers

\mathrm{GaAs}