Epitaxial thin films of stoichiometric LaMnO 3 were grown on SrTiO 3 (110) substrates using the pulsed laser deposition technique. From the high resolution x-ray diffraction measurements, the lattice parameters were determined as a function of temperature and the cooperative JahnTeller transition was found to occur at T JT =573.0 K. Also measured was resonant x-ray scattering intensity of the orthorhombic (100) peak of LaMnO 3 near the Mn K edge from low temperatures to above T JT . We demonstrate that the integrated intensity of the (100) peak is proportional to the 3/2 power of the orthorhombic strain at all temperatures, and thus provide an experimental evidence that the resonant scattering near the Mn K edge in LaMnO 3 is largely due to the JahnTeller effect.

No abstract

The electronic density of states in BaTiO 3 is studied by means of X-ray absorption near-edge structure in a vicinity of a Ti K edge and Ba L edges. A 4pπ band of the Ti ion and a 5dπ band of the Ba ion having a high-density unoccupied state occupy a level just above the Fermi level (E F ). The pre-edge peaks give that, in addition to an O 2-2p valence band, the electronic density of states below E F are composed of negativecharge-transfer bands 3d 2 bands in the ferroelectric phase suggests that the collective displacement of Ba ions from ideal ionic sites of the cubic perovskite-type structure reduces the hybridization between the Ba and O ions. This gives that the effective charge on the O ions is increased and induces a large dipole moment between the O ions and the Ti ions, which are at an off-center position of TiO 6 octahedra in the ferroelectric phase.

A Co/Pt multilayer with strong perpendicular magnetic anisotropy was prepared by electron beam evaporation. Using polarized extended x-ray absorption fine structure (EXAFS) measurements at the Co K edge, the interface structure of the Co/Pt multilayer was investigated. In quantitative analysis, the EXAFS data measured with in-plane polarization showed considerable intermixing at the Co/Pt interfaces, while those measured with out-of-plane polarization indicated an abrupt interface structure. More detailed atomic configurations of the Co/Pt interface were simulated using the measured coordination numbers. The results of the computer simulation showed that the Pt clusters in Co layers and the Co clusters in Pt layers were interfacing. With the obtained structural information and a symmetry-based Néel model, the magnetic anisotropy of the multilayer was estimated. The estimated magnetic anisotropy was consistent with the measured one.

No abstract