Ordering on geometrically frustrating lattices: The perspective of TOF neutron crystallography

DOI: 10.1016/j.physb.2006.05.092

Authors: Paolo G. Radaelli (ISIS Facility) , Laurent Chapon (ISIS Facility) , Matthias Gutmann (ISIS Facility) , Alessandro Bombardi (Diamond Light Source) , Graeme Blake (ISIS Facility) , Marek Schmidt (ISIS Facility) , Sang-Wook Cheong (Rutgers University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physica B: Condensed Matter , VOL 385-386 , PAGES 29 - 34

State: Published (Approved)
Published: November 2006

Abstract: Geometrical frustration arises when geometrical constraints promote a locally degenerate ground state. A periodic system with this local geometry may “freeze” on cooling forming “ices” or remain liquid down to the lowest temperatures due to quantum effects. A third possibility is that of a structural phase transition that lowers the local symmetry and lifts the degeneracy. Two classic examples of geometrical frustration are the so-called pyrochlore lattice, which is also found in AB2X4 spinels, and the “J1–J2” model on a square lattice, which involves competing nearest- and next-near-neighbor magnetic interactions. We present recent results obtained by time-of-flight (TOF) neutron powder diffraction on orbital ordering in transition-metal spinels, leading to the concept of orbitally-driven Peierls state, and more recent data on MoOVO4, a realization of the J1–J2 model. A surge of interest in the so-called multiferroic materials has led to revisit the role of geometrical frustration in coupling different degrees of freedom. In this context, we present recent results on REMn2O5 obtained by neutron single-crystal and powder diffraction.

Journal Keywords: Geometrical Frustration; Multiferroics; Magnetic Structures

Subject Areas: Physics, Materials

Facility: GEM at ISIS

Added On: 10/11/2010 08:51

Discipline Tags:

Quantum Materials Multiferroics Physics Magnetism Materials Science

Technical Tags: