Determination of the spin polarization of half-metallic CrO2 by point contact Andreev reflection

Andreev reflection at a Pb/CrO2 point contact has been used to determine the spin polarization of single-crystal CrO2 films made by chemical vapor deposition. The spin polarization is found to be 0.96 +/- 0.01, which confirms that CrO2 is a half-metallic ferromagnet, as theoretically predicted.