Near-complete spin polarization in atomically-smooth chromium-dioxide epitaxial films prepared using a CVD liquid precursor

Abstract

We have fabricated single crystal chromium dioxide $({\mathrm{CrO}}_{2})$ films using chemical vapor deposition with chromyl chloride $({\mathrm{CrO}}_{2}{\mathrm{Cl}}_{2})$ as a liquid precursor. Their electrical and magnetic properties have been investigated. These films are atomically smooth with a rms roughness of less than 5 \AA{} for 1000 \AA{} thick films. We have obtained a spin polarization of $P=98.4%,$ as determined by the technique of point-contact Andreev reflection. Magnetization and resistivity measurements on these films are in good agreement with those measured on films made with the ${\mathrm{CrO}}_{3}$ solid precursor. The process using the liquid precursor is superior to other existing techniques for the preparation of single crystal single- and multilayers containing ${\mathrm{CrO}}_{2},$ especially the structure of magnetic tunnel junctions.