Ferromagnetic semiconductor GaMnAs

Large tunneling magnetoresistance in GaMnAs/AlAs/GaMnAs ferromagnetic semiconductor tunnel junctions

We have observed very large tunneling magnetoresistance (TMR) in epitaxially grown Ga1−xMnxAs/AlAs/Ga1−xMnxAs ferromagnetic semiconductor tunnel junctions. Large TMR ratios more than 70% were obtained in junctions with a very thin (5 1.6 nm) AlAs tunnel barrier when the magnetic field was applied along the [100] axis in the film plane. The TMR was found to rapidly decrease with increasing the b...

Ferromagnetic Resonance Investigation of GaMnAs Nanometric Layers

This thesis is dedicated to the study of the magnetic properties of GaMnAs nanometric layers by the ferromagnetic resonance (FMR) technique. Three series of samples have been studied to investigate independently the influence of the strain, the hole concentration and the Mn concentration on the magnetic properties of GaMnAs. In the first series, the Ga1−xMnxAs samples with x=0.07, grown on GaAs...

Memory effects in photoinduced femtosecond magnetization rotation in ferromagnetic GaMnAs

in ferromagnetic GaMnAs J. Wang, I. Cotoros, D. S. Chemla, X. Liu, J. K. Furdyna, J. Chovan, and I. E. Perakis Department of Physics and Astronomy and Ames Laboratory-USDOE, Iowa State University, Ames, Iowa 50011, USA Department of Physics and Materials Sciences Division, E.O. Lawrence Berkeley National Laboratory, University of California at Berkeley, Berkeley, California 94720, USA Departmen...

Large magnetoresistance in a ferromagnetic GaMnAs/GaAs Zener diode

–We investigate spin-dependent interband tunnelling in a ferromagnetic (Ga,Mn)As/ GaAs Zener diode. The ferromagnetic pn-junction is fabricated with a Mn-doped p-type GaAs layer on top of a nonmagnetic n-type GaAs substrate. When both sides of the junction are heavily doped, a large magnetic-field–dependent tunnelling effect can be seen at low temperatures in the measured current-voltage (I-V )...

Josephson Current in a Ferromagnetic Semiconductor/Semiconductor/Ferromagnetic Semiconductor Junction with Superconducting Contacts