  We report a detailed high-temperature powder neutron diffraction
investigation of the structural behavior of the multiferroic GaFeO3 between 296
and 1368 K. Temperature dependent neutron diffraction patterns do not show any
appreciable change either in intensity or appearance/disappearance of the
observed peaks upto 1368 K, ruling out any structural transition in the entire
temperature range. The lattice parameters and volume exhibit normal thermal
expansion behaviour, indicating the absence of any structural changes with
increasing temperature. The origin of the magnetoelectric couplings and
multiferroicity in GaFeO3 is known to be influenced by the site disorder from
Ga/Fe atoms. Our analysis shows that this disorder remains nearly the same upon
increase of temperature from 296 to 1368 K. The structural parameters as
obtained from Rietveld refinement of neutron diffraction data are used to
calculate the interatomic distances and distortions of the oxygen polyhedra
around the Ga1, Ga2, Fe1 and Fe2 cations. Evolution of the distortion of the
oxygen polyhedra around these sites suggests that the Ga1-O tetrahedron is
least distorted and Fe1-O is most distorted. Structural features regarding the
distortion of polyhedral units would be crucial to understand the temperature
dependence of the microscopic origin of polarizations. The electric
polarization has been estimated using a simple ionic model and its value is
found to decrease with increasing temperature.
