2005/02/23 by R. P. Panguluri, Raghava P. Panguluri, K. C. Ku +9
Physics and Astronomy · #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.72.054510
arxiv created 2005/02/23 · openalex publication_date 2005/08/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate the applicability of spin-polarization measurements using Andreev reflection in a point-contact geometry in heavily doped dilute magnetic semiconductors, such as (Ga,Mn)As. Although we observe conventional Andreev reflection in nonmagnetic (Ga,Be)As epilayers, our measurements indicate that in ferromagnetic (Ga,Mn)As epilayers with comparable hole concentration the conductance spectra can only be adequately described by a broadened density of states and a reduced superconducting gap. We suggest that these pair-breaking effects stem from inelastic scattering in the metallic impurity band of (Ga,Mn)As and can be explained by introducing a finite quasiparticle lifetime or a higher effective temperature. For (Ga,Mn)As with 8% Mn concentration and 140\phantom\rule0.3em0exK Curie temperature we evaluate the spin polarization to be 83\ifmmode±\else\textpm\fi17%.