Tailoring Spin Relaxation in Thin Films by Tuning Extrinsic Relaxation Channels
The importance of extrinsic spin relaxation processes such as magnon-magnon scattering for the overall damping in ferromagnetic thin films has been shown for low relaxation rate systems. Due to its anisotropic behavior, it offers an opportunity for controlling and tailoring the spin relaxation. In this paper, a ferromagnetic resonance study of a system with pure Gilbert damping Fe94.5Si5.5/MgO(001) is shown. Fe3Si/MgO(001) systems with native magnon-magnon scattering are discussed. Possibilities for inducing magnon-magnon scattering by volume and surface defects in these systems are presented, offering a method for controlled tailoring of the overall damping in thin films.
Spin Dynamics in the Time and Frequency Domain
The current status of experimental approaches to analyze the spin wave dynamics in ferromagnetic nanoscale structures is reviewed. Recent developments in frequency- and field swept spectroscopy to determine the resonant response of nanoscale ferromagnets are described together with time-resolved measurements in the GHz frequency and pico second time domain, respectively. Examples for the analysis and manipulation of different mechanisms for the relaxation of the magnetization after microwave excitation into its ground state are presented.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.