J. J. Neumeier

Lattice effect in perovskite and pyrochlore CMR materials

Colossal magnetoresistance (CMR) in doped La manganite thin films (La{sub 1-x}M{sub x}MnO{sub 3}, where M = divalent ion, either Ca or Pb) has been shown to result in a factor of 10{sup 6} suppression of the resistance. The driving force for the CMR transition is thought to be the double-exchange interaction. Many studies of both the crystal structure and the local structure of the La{sub 1-x}M{sub x}MnO{sub 3} (M = Ca, Sr, Ba, Pb) system have now been carried out. As expected, these systems all show a strong coupling of the lattice to the CMR transition. On the other hand, neutron diffraction and x-ray absorption for the Tl{sub 2}Mn{sub 2}O{sub 7} pyrochlore, which also exhibits CMR, shows no deviations from ideal stoichiometry, mixed valency, or Jahn-Teller distortions of the MnO{sub 6} octahedron. We present results of crystallographic and local structural studies of these two important classes of CMR materials, compare the differences in structural response, and discuss the implications of these findings to our understanding of these materials.

Temperature dependent changes of the Mn3dand4pbands nearTcin colossal magnetoresistance systems: XANES study ofLa1−xCaxMnO3

We report high-resolution x-ray-absorption near-edge structure measurements at the Mn K edge as a function of temperature, for

Local structure and polaron formation in La1−xCaxMnO3

{\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}

Interplay between electronic transport and magnetic order in ferromagnetic magnetic manganite thin films

samples, with a focus mainly on the pre-edge region. Small peaks labeled

Lattice coupling to electronic and magnetic instabilities in high magnetic fields

{A}_{1}--{A}_{3}

Direct Observation of Lattice Polaron Formation in the Local Structure of La{sub {bold 1{minus}}{ital x}}Ca{sub {ital x}}MnO{sub {bold 3}}

are observed which correspond to

SUBSTANTIAL PRESSURE EFFECTS ON THE ELECTRICAL RESISTIVITY AND FERROMAGNETIC TRANSITION TEMPERATURE OF LA1-XCAXMNO3

1s\ensuremath{-}3d

Direct Relationship between Magnetism and MnO 6 Distortions in La 1 − x Ca x MnO 3

dipole transitions, made weakly allowed via a hybridization of Mn

Phonon Raman scattering in R{sub 1{minus}x}A{sub x}MnO{sub 3+{delta}} (R=La,Pr; A=Ca,Sr)

4p

Direct Relationship between Magnetism and MnO{sub 6} Distortions in La{sub 1{minus}{ital x}}Ca{sub {ital x} }MnO{sub 3}

states with Mn