Papers by Author: Yukari Fujioka

Abstract: The effect of manganese doping on the magnetic and structural properties of strontiumtitanate (SrTiO3) was studied. Neutron powder diffraction, x-ray diffraction, magneticmeasurements, scanning electron microscopy and energy dispersive spectroscopy of x-rays wereutilized. Air-sintered Sr(MnxTi1-x)O3 (SMT) with x = 0:02 and x = 0:05 were homogeneoussingle phase orthorhombic (space group Pbnm) perovskite samples. The symmetry was orthorhombicalready at room temperature, and no symmetry change was observed down to 11K. An anomaly in the magnetic susceptibility was observed in x = 0:02 sample at 75 K. Incontrast to earlier reports, no ferromagnetism was observed.

Abstract: Ti-rich Mg1ЎxTi1+xO3 samples were synthesized by solid-state reaction. Sampleswere characterized by room temperature x-ray powder di®raction, scanning electron microscopyand energy dispersive spectroscopy of x-rays. Hexagonal lattice parameters a and c increasedwith increasing Ti content. Time-of-Flight-Secondary-Ion-Mass-Spectroscopy (ToF-SIMS, de-tection limit 10Ў6) measurements revealed that no magnetic impurities were present. Sampleswith x = 0:10; 0:12 and 0:32 showed ferromagnetic hysteresis loops. The result demonstratesthat excess Ti at the Mg-O cation layer controls the magnetic properties. This is a technologicaladvantage especially for thin Їlm applications.