Electronic structure and magnetism of SrTi_(1-x)Mn_xO_3 ceramics

摘要

Having reviewed the previous studies on Mn-doped SrTiO3 materials, we found that Mn2+ and/or Mn4+ ions are usually present in the SrTiO3 host lattice and lead to paramagnetic, spin-glass, or ferromagnetic (FM) behavior. Mn2+ can occupy at both octahedral (Ti) and dodecahedral (Sr) sites, while Mn4+ only occupies the Ti site. To get more insight into this material system, we have prepared polycrystalline SrTi1-xMnxO3 (x = 0-0.10) samples by solid-state reactions. The results obtained from analyzing the powder X-ray diffraction patterns, and Raman scattering, X-ray absorption, and electron-spin-resonance spectra indicate an incorporation of Mn2+ and Mn3+ ions into the SrTiO3 host lattice. Isolated Mn2+ ions are dominant in the samples with x = 0.02 and can occupy both Ti and Sr sites, leading to two sets of the hyperfine sextet lines. An increase in the Mn content with x 0.02 enhances the Mn3+ concentration and stimulates the formation of a minor tetragonal phase besides the main cubic phase of SrTiO3. This enhances the Lorentzian-shaped broad background line of dipolar and magnetic interactions between Mn ions. Besides the resonant signals of isolated Mn2+ ions and dipolar/magnetic interactions between Mn ions, there is also the resonant signal associated with intrinsic defects. We believe that intrinsic defects together with the Mn doping at suitable concentrations (x 0.02) are an important pivot for tailoring room-temperature FM order in SrTi1-xMnxO3 ceramics. Published by AIP Publishing.