Hydrogen-mediated ferromagnetism in ZnO single crystals

New J. Phys. 13, 063017 (2011)

M. Khalid, P. Esquinazi, D. Spemann, W. Anwand and G. Brauer


We investigated the magnetic properties of hydrogen-plasma-treated ZnO single crystals by using superconducting quantum interferometer device magnetometry. In agreement with the expected hydrogen penetration depth, we found that ferromagnetic behavior is present in the first 20 nm of the H-treated surface of ZnO with magnetization at saturation up to 6 emu g−1 at 300 K and a Curie temperature of Tcgsim400 K. In the ferromagnetic samples, a hydrogen concentration of a few atomic per cent in the first 20 nm of the surface layer was determined by nuclear reaction analysis. The saturation magnetization of H-treated ZnO increases with the concentration of hydrogen.