X-ray and neutron scattering

Abstract:

Magnetoelectronic phase separation plays an integral part in many recent advances in the understanding of correlated electron systems. We have studied the magnetically phase separated material La1-x Srx Co O3 and observe unambiguous evidence of magnetic interactions between hole-rich ferromagnetic clusters and the neighboring hole poor matrix. We suggest that this mechanism detected here plays an important role in the rich electrical and magnetic properties of La1-x Srx Co O3. © 2006 The American Physical Society.

Abstract:

The structure of bilayer manganite LaSr2Mn2O7 has been investigated under high pressure using synchrotron and laboratory X-rays in the angle-dispersive X-ray diffraction geometry up to 35 GPa at ambient temperature. The Rietveld refinement results of the powder diffraction data show a crossover between the axial and equatorial Mn-O bond length values and a significant suppression of Jahn-Teller (JT) distortion around 16 GPa. Our results imply that a re-entrant behavior in LaSr2Mn2O7, which shows equality in all the three Mn-O bond length values around 16 GPa similar to ambient conditions, may dramatically alter the orbital ordering. Further, the P-V data for the bilayer compounds indicate that the additional substitution of La3+ for Sr2+ lowers the bulk modulus and enhances lattice softening. © 2006 Elsevier Ltd. All rights reserved.