Phase Stability of Multiferroic GaFeO3 up to 1368 K from In situ Neutron Diffraction

Abstract

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.

16 Pages, 9 Figures

References in corpus (2)

• Electronic Structures, Born Effective Charges and Spontaneous Polarization in Magnetoelectric Gallium Ferrite
• High-Temperature Phonon Spectra of Multiferroic BiFeO3 from Inelastic Neutron Spectroscopy

Cited by in corpus (6)

• Room Temperature Nanoscale Ferroelectricity in Magnetoelectric GaFeO3 Epitaxial Thin Films
• Spin-Phonon Coupling, High Pressure Phase Transitions and Thermal Expansion of Multiferroic GaFeO3: A Combined First Principles and Inelastic Neutron Scattering Study
• Room-temperature multiferroicity in GaFeO${}_3$ thin film grown on (100)Si substrate
• Heat capacity anomaly near magnetic phase transition in GaFeO${}_3$
• Electrical polarization switching in bulk single crystal GaFeO${}_3$
• Mössbauer measurements of GaFeO${}_3$ single crystal multiferroic