Particles-Matrix Bond in ZnCoO:H and ZnCoAlO:H Films: Issues of Magnetism and Spin Injection.

ZnCoO:H and ZnCoAlO:H films were synthesized by radio frequency magnetron sputtering in a (1 - x)Ar + xH mixed atmosphere with x = 0.2-0.5.

Theoretical model investigating the magnetic properties of cobalt-doped ZnO.

We propose a theoretical model to investigate the magnetic properties of cobalt-doped ZnO (ZnO:Co) thin films qualitatively. The model was built on the dilute Co dopants in the host of ZnO forming the magnetic Co ions and the energy level of the magnetic ions crossing the band edge of ZnO resulting in a magnetic interaction between the Co spins and the spins of the electrons from the conduction band of ZnO. The mechanism of the ferromagnetism revealed in the studied system is proposed here to be induced not only by the mediated conducting electrons via spin interactions but also by the Coulomb excitations, arising from the electrons localized by the oxygen vacancies.

Theoretical investigation of Hall sign change in SrRuO.

The appearance of Hall sign change in perovskite SrRuO thin films at Curie temperature was confirmed from our fabricated samples and the result was simulated by our proposed theoretical model. In particular, our simulation results are consistent with experimental results mainly due to the introduction of an impurity band in a two-band model. We found the other important factors in our theory responsible for observed consistency Hall measurements are the itinerant carrier density and its intrinsic carrier type.

Origin of abnormal structural transformation in a (BiPb)FeO/SrRuO/SrTiO hetero-structure probed by Rutherford backscattering.

Scientific efforts are growing to understand artificial BiFeO/SrRuO/SrTiO-heterostructures, wherein an altered environment at each interface, caused by epitaxial strains, broken symmetry, off-stoichiometry and charge transfer, can generate a rich spectrum of exotic properties. Herein, (BiPb)FeO/SrRuO/SrTiO-heterostructures were sputtered with various top (BiPb)FeO-layers at different growth temperatures (T ). Strain relaxation at each interface changes with T and generates an additional peak alongside with (BiPb)FeO at a high T of 700 °C.

Instrument for x-ray absorption spectroscopy with in situ electrical control characterizations.

We report a synchrotron-based setup capable of performing x-ray absorption spectroscopy and x-ray magnetic circular dichroism with simultaneous electrical control characterizations. The setup can enable research concerning electrical transport, element- and orbital-selective magnetization with an in situ fashion. It is a unique approach to the real-time change of spin-polarized electronic state of a material/device exhibiting magneto-electric responses.

Short range magnetic correlations induced by La substitution in Ho(1-x)La(x)Mn(2)O(5).

Magnetic susceptibility, x-ray diffraction, neutron diffraction and Raman scattering measurements are employed to study the effects of La substitution on the magnetic properties of multiferroic HoMn(2)O(5). 9% and 18% La-substituted compounds crystallize into the same orthorhombic Pbam symmetry as the parent compound. The magnetic responses to an ac driving magnetic field between 40 and 140 K are greatly enhanced by 18% La substitution.