Magnetism in Ni-doped SnO2 thin films

Transparent Ni-doped SnO2 thin films grown by the pulsed laser deposition technique on LaAlO3, SrTiO3 as well as R-cut Al2O3 substrates all show room-temperature ferromagnetism (FM). While the Ni-doped SnO2 films on LaAlO3 substrates have a large magnetic moment of about 2 mu(B)/Ni, films grown under the same conditions on SrTiO3 and Al2O3 substrates have a magnetic moment of one order smaller. Magnetic force microscopy measurements confirmed that the Ni:SnO2 films on LaAlO3 are magnetically homogeneous at nanometrescales, and the FM in the films comes from the doped matrix.