Single Crystal Growth and Properties of BaFeGaO4 using The Floating Zone Technique

Materials with topological spin textures are in demand for applications like memory storage and quantum computing. The AB2O4 family of crystals has a spinel structure and has been extensively examined. However, there are cases where the typical spinel structure is replaced with a tetrahedral network. The cubic ferromagnetic CuOSeO3 has been previously shown to contain skyrmions. BaFeGaO4 (BFGO) is being grown to better characterize its magnetic and thermal properties.<br/><br/>We have successfully developed a polycrystalline sample of BFGO using the solid state method. Polycrystalline samples were prepared using stochiometric quantities of BaCO3, Fe2O3, and Ga2O3. Since BaCO3 decomposes at 1000 C, samples were annealed for 6 hours to convert it to BaO. The powder mixture was annealed twice at 1100 C, with intermediate grindings after each step. Growth rods were prepared by pressing the powder with a hydraulic press into rods approximately 6 mm in diameter and 5 cm in length.<br/>BFGO crystallizes in the hexagonal crystal system with space group P63. Structural analysis revealed that the samples had the correct structure. Rietveld analysis of X-ray diffraction also indicated single phase samples. BFGO belongs to the hexagonal structure having space group P63. Lattice parameters at room temperature: a = 10.8137 (6) A and c = 8.6734 (5) A.<br/><br/>Magnetic measurements were conducted with a Quantum Design Dynacool PPMS. The BFGO sample shows an upturn in the magnetic susceptibility near 50 K, evidence of magnetic ordering. The M-H hysteresis curve was observed at a temperature of 2 K, indicating that the sample is ferromagnetic. To understand the underlying physics and intrinsic behavior of BFGO, a single crystal is needed. Therefore, single crystals of BaFeGaO4 are being grown using the floating zone technique to control the spinel structural phase and characterize its morphology, thermal, magnetic, and electronic properties. Results of single crystal growth will be presented.