Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
2008-04-11
J. Phys.: Condens. Matter 20, 235210 (2008)
Physics
Condensed Matter
Strongly Correlated Electrons
Accepted to Journal of Physics: Condensed Matter
Scientific paper
10.1088/0953-8984/20/23/235210
The crystal structures of the A2B2O7-x Niobium-based pyrochlores Y2(Nb0.86Y0.14)2O6.91, CaYNb2O7, and Y2NbTiO7 are reported, determined by powder neutron diffraction. These compounds represent the first observation of B-site displacements in the pyrochlore structure: the B-site ions are found to be displaced from the ideal pyrochlore positions, creating electric dipoles. The orientations of these dipoles are fully analogous to orientations of the magnetic moments in Ising spin based magnetically frustrated pyrochlores. Diffuse scattering in electron diffraction patterns shows that the displacements are only short range ordered, indicative of geometric frustration of the collective dielectric state of the materials. Comparison to the crystal structure of the Nb5+ (d0) pyrochlore La2ScNbO7 supports the prediction that charge singlets, driven by the tendency of Nb to form metal-metal bonds, are present in these pyrochlores. The observed lack of long-range order to these singlets suggests that Nb4+-based pyrochlores represent the dielectric analogy to the geometric frustration of magnetic moments observed in rare earth pyrochlores.
Cava Robert. J.
Huang Qingzhen
McQueen T. M.
Muegge B.
Noble K.
No associations
LandOfFree
Frustrated Ferroelectricity in Niobate Pyrochlores does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Frustrated Ferroelectricity in Niobate Pyrochlores, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Frustrated Ferroelectricity in Niobate Pyrochlores will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-706946