ИСТИНА

We review our recent experimental results on the structural, magnetic, magnetotransport and magnetooptical properties of Mn-implanted Si wafers, thin films Si1-xMnx (х = 0.44-0.60), and Co-and V-doped TiO2 magnetic oxides. The Si wafers, both n- and p-type, with high and low resistivity, were used as the starting materials for implantation with Mn ions at the fluencies up to 5 x 1016 cm-2. After implantation and vacuum annealing at 8500C, the materials were investigated with SIMS, SRP, TEM, XRD, XAS, XMCD, VSM, SQUID and magneto-optical techniques [1]. The saturation magnetization was found to show the lack of any regular dependence on the Si conductivity type, type of impurity and the short post- implantation annealing. According to XMCD Mn impurity in Si does not bear any appreciable magnetic moment at room temperature. The obtained results indicate that above room temperature ferromagnetism in Mn-implanted Si originates not from Mn impurity but rather from structural defects in Si. The diluted oxides TiO2-d:Co and TiO2-d:V thin films were deposited by magnetron sputtering in the argon–oxygen atmosphere at oxygen partial pressure of 2.10-6-2.10-4 Torr. It was obtained that Transversal Kerr Effect (TKE) spectra in ferromagnetic samples TiO2-d:Co are extremely sensitive to the Co volume fraction, the crystalline structure, and technology parameters. The observed well-pronounced peaks in TKE spectra for anatase Co-doped TiO2-d films at low Co (<1%) volume fraction are not representative for bulk Co or Co clusters in TiO2-d matrix that indicates on intrinsic ferromagnetism in these samples. With increase of Co volume fraction up to 5-8% the fine structure of TKE spectra disappears and the magneto-optical response in reflection mode becomes larger than that for thick Co films. Contrary to Co doping no appreciable magnetic moment on V impurities was found by XMCD technique. Magnetic, magneto-optical and magnetotransport properties in V-doped TiO2-d are less pronounced than in TiO2-d:Co and clearly indicate on different origin of ferromagnetism in TiO2﷓d:Co and TiO2﷓d:V. Thin films Si1-xMnx (х = 0.44-0.6) were obtained by pulse laser deposition [2]. The nonstoichiometric compositions are ferromagnetic at room temperature and exhibit TKE and anomalous Hall effect [3]. The obtained data indicate on the defect-induced intrinsic above room temperature ferromagnetism even at a small nonstoichiometry. This work was partly supported by the Russian Foundation for Basic Research grants 13-02-92694, 13-07-00477, 13-02-00016, 13-02-00655, and by the HGF-RFBR project “DETI.2” (HRJRG-314 & RFBR #12-02-91321-SIG_a). References 1. A. Granovsky, A.Orlov, N. Perov et al., J. Nanosci. Nanotechn. 12, 7540 (2012). 2. B.A. Aronzon, V.V. Rylkov, S.N. Nikolaev et al., Phys. Rev. B 84, 075209 (2011). 3. V.V. Rylkov, E.A. Gan’shina, O.A. Novodvorskii et al., Eur. Phys.Lett. 103, 57014 (2013).