ABSTRACT
Positron spin spectroscopy is based on the process of positron–electron annihilation, which is dependent on the electron density at the annihilation site. Spin-resolved positron spectroscopy allows one to analyze the electronic structure of magnetic materials, enabling the measurements of PN in a wide temperature range. Spin-resolved photoemission spectroscopy is also, in principle, capable of measuring PN The chapter examines the discussion of point contact Andreev reflection spectroscopy, one of the commonly used techniques to measure spin polarization. Andreev reflection, named after Alexander F. Andreev, was introduced in 1964 to explain the puzzling effects of anomalously high thermal resistance in the intermediate state of type-I superconductors, which greatly exceeded the thermal resistance in the superconducting state. While the conductance broadening observed in Ga/As was attributed primarily to the distribution of the critical temperatures in amorphous Ga used as a superconducting contact, additional inelastic broadening effects are also possible.
