The effect of oxygen on the Jahn-Teller distortion and magnetization dynamics of Pr0.9Ca0.1MnO3 thin films.

We report on the effect of oxygen on the Jahn-Teller distortion and dynamic magnetic properties of low hole-doped Pr(0.9)Ca(0.1)MnO(3) thin films, using micro-Raman spectroscopy and the temperature dependent ac susceptibility, as a function of the frequency, dc field bias, and thermal cycles. The as-grown and vacuum annealed thin films show a high amount of magnetic frustration and inferior ferromagnetic ordering compared with the oxygen annealed thin films. It has been found that the amount of magnetic frustration in the film is interlinked with the Jahn-Teller distortion and domain wall dynamics. An attempt has been made to understand the origin and nature of the magnetic frustration.

The local metallicity of gadolinium doped compound semiconductors.

The local metallicities of Hf(0.97)Gd(0.03)O(2), Ga(0.97)Gd(0.03)N, Eu(0.97)Gd(0.04)O and EuO films were studied through a comparison of the findings from constant initial state spectroscopy using synchrotron light. Resonant enhancements, corresponding to the 4d → 4f transitions of Eu and Gd, were observed in some of the valence band photoemission features. The resonant photoemission intensity enhancements for the Gd 4f photoemission features are far stronger for the more insulating host systems than for the metallic system Eu(0.96)Gd(0.04)O. The evidence seems to suggest a correlation between the effective screening in the films and the resonant photoemission process.