High field magnetotransport and point contact Andreev reflection measurements on CuCr2Se4 and CuCr2Se 3Br - Degenerate magnetic semiconductor single crystals

Abstract

Single crystals of the metallically degenerate fully magnetic semiconductors CuCr2Se4 and CuCr2Se3Br have been prepared by the Chemical Vapour Transport method, using either Se or Br as transport agents. The high-quality, millimetre-sized, octahedrally faceted, needle- and platelet-shaped crystals are characterised by means of high field magnetotransport ( 14 T) and Point Contact Andreev Reflection. The relatively high spin polarisation observed , together with the relatively low minority carrier effective mass of 0.25 me , and long scattering time , could poise these materials for integration in low- and close-to-room temperature minority injection bipolar heterojunction transistor demonstrations.