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Investigation of Ga2-xFexO3 single crystals grown by floating zone method
|Srimathy Balasubramanian 1, Indranil Bhaumik 2, Ganesamoorthy Sarveswaran 3, Rajeev Bhatt 2, Karnal Ak 2, Kumar Janakiraman 1|
1. Crystal Growth Centre, Anna University, Chennai, Chennai 600025, India
Gallium iron oxide (Ga2-xFexO3, 0.7 ≤ x ≤ 1.4) is a piezoelectric ferromagnetic compound exhibiting large magnetoelectric (ME) effect. These kind of magnetoelectric materials find applications in new kind of multistate non-volatile memories such as magnetically tunable ferroelectric random access memories, electrically tunable magnetic random access memories and high frequency filters, etc. Single crystals of Ga2−xFexO3 with x = 0.8, 1 and 1.2 were successfully grown by a Optical Floating Zone (OFZ) method under a high oxygen pressure of 9–10 atm. Figure 1 shows the picture of as grown GaFeO3 single crystal. From the powder X-ray diffraction measurements, it was confirmed that the grown crystals are in single phase. All the peaks were indexed by the Pc21n orthorhombic unit cell of Ga2−xFexO3. Lattice parameters were obtained by Rietveld refinement. The chemical compositions of the crystals were determined by energy dispersive X-ray spectrum (EDAX). Uniform growth steps were seen on the surface of the crystal along the growth direction. Etching studies were carried out at various temperatures with H3PO4 and mixture of H3PO4 and HNO3 as etchants. Etch pit rows were observed to be circular and shallow. With increase in temperature of the etchant, the time to nucleate an etch pit decreased. Figure 2 shows the variation of dielectric constant (ε’) and dielectric loss factor (tan δ) with temperature at different frequencies for GaFeO3. ε’ clearly showed a Debye-like relaxation and enhancement of hopping conduction. With increase in x for Ga2-xFexO3, ε’ and tan δ increases considerably. Magnetization showed a well saturated hysteresis loop at room temperature for the single crystals which are investigated in detail.
Presentation: Oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 6, by Kumar Janakiraman
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17
Submitted: 2013-04-09 11:35 Revised: 2013-07-23 18:14