ИСТИНА

Since the pioneering paper of Y.Matsumoto [1] there was an increasing activity in studying above room-temperature magnetism in titanium dioxide thin films doped by 3d impurities – cobalt, iron, vanadium or manganese. It was widely believed that the origin of long-range magnetic order in these systems does not depend on the type of 3d impurity. To explain experimental data several models like carrier-mediated ferromagnetism, magnetic polarons, kinetic exchange, superexchange, charge-transfer ferromagnetism, magnetic foam were proposed (see [2] for a brief review). Nevertheless, high Curie temperatures, large magnetic moments per impurity atom and specific features in magnetic, transport and magneto-optical properties are still far from being well understood. Moreover, contrary to TiO2-delta : Co thin films that were widely studied either experimentally or theoretically by different groups, only several controversial results for TiO2-delta : V films are presented in the literature [3,4]. We report our last experimental results on magnetic, magneto-transport, magneto-optical and element-selective properties of TiO2-delta : Co and TiO2-delta : V thin films with a small fraction (1%) of Co and V, correspondingly. The studied diluted oxides were prepared by rf magnetron sputtering technique. It has been discovered that magnetic properties of Co- and V-doped TiO2-delta samples are significantly different: the magneto-optical response of TiO2-delta : V is at least one order of magnitude weaker in comparison with TiO2-delta : Co and XMCD technique has not revealed any appreciable magnetic moment on V impurities, while the values of magnetic moment per impurity are at the same level for both systems.