We report measurements of long ranged supercurrents through ferromagnetic and fully spin-polarized CrO2 deposited on TiO2 substrates. In earlier work, we found supercurrents in films grown on sapphire but not on TiO2. Here, we employed a special contact arrangement, consisting of a Ni/Cu sandwich between the film and the superconducting amorphous Mo70Ge30 electrodes. The distance between the contacts was almost a micrometer, and we find the critical current density to be significantly higher than found in the films deposited on sapphire. We argue this is due to spin mixing in the Ni/Cu/CrO2 layer structure, which is helpful in the generation of the odd-frequency spin triplet correlations needed to carry the supercurrent.
Anwar, M. S., Veldhorst, M., Brinkman, A., & Aarts, J. (2012). Long range spin supercurrents in ferromagnetic CrO2 using a multilayer contact structure. Applied physics letters, 100(5), 052602-. . https://doi.org/10.1063/1.3681138