2, Geophysical Laboratory, Washington, District of Columbia, United States
3, Department of Physics and Astronomy, Morgantown, West Virginia, United States
The quest for the search of multiferroic materials with transition temperatures above room temperature are due to their technological importance and novel applications such as in sensors and logic, memories and multifunctional devices. Gallium Ferrite (GaFeO3, GFO) is known to be piezoelectric and it is near room temperature ferrimagnetic with significant magnetoelectric (ME) coupling (10−11 s/m at 4.2 K). Herein phonons, magnetic ferroelectric ordering in perovskite GFO have been investigated using magnetization, dielectric and Raman scattering measurements as a function of temperature. Single phase GFO ceramics is prepared by solid state reaction method at optimized calcined temperature of 1573 K. Studies of X-rays patterns indicated that the titular compound stabilizes in orthorhombic phase (space group C2v9). Stoichiometry of the elemental composition is confirmed using energy dispersive X-rays analysis and X-ray photoelectron spectroscopic techniques. Temperature dependent magnetization behavior studied at both field-cooled and zero-field-cooled conditions between 5- 395 K using several static magnetic fields (such as 100 Oe, 500 Oe and 1000 Oe) identify the Néel transition (TN) at around 225 K. Evidence of spin-glass like magnetic ordering is observed at low temperature. Phonon frequencies and its line-widths exhibit anomaly across TN. The changes in phonon frequencies observed in Raman scattering are explained based on spin-lattice coupling in the low temperature ferrimagnetic phase. Examination of the phonon behavior indicates that three phonon anharmonicity process is dominant. The temperature and frequency dependent dielectric measurements indicated a dielectric anomaly at around 590 K suggesting that the system exhibits ferroelectric relaxor behavior. The detailed experimental results and their physical correlations will be presented in the meeting.