Magnetic, structural, electronic, and optical investigations of Ti_(1-x)Mn_xO_2 films

摘要

Observation of room temperature ferromagnetism (RTFM) is reported in polycrystalline thin films of Ti_(1-x)Mn_xO_2 (x = 0.10 and 0.15) synthesized by spray pyrolysis technique on fused quartz substrates. Our experimental results clearly suggest partial incorporation of manganese (Mn) in titanium dioxide (TiO_2) lattice up to certain extent and rest of the Mn ions are consumed to form secondary Mn-related phase such as manganese oxide (Mn_3O_4). The observed weak ferromagnetic ordering at room temperature in the films is established to be due to incorporation of Mn in TiO_2 matrix rather than the presence of other secondary phases since none of the Mn or Ti/Mn oxide phase is ferromagnetic at room temperature. Bound magnetic polaron model is invoked to explain the observed ferromagnetism in these highly resistive films.