Homogeneity of YGaIG single crystal grown by the FZ method

Single crystals of gallium-substituted yttrium iron garnet (YGaIG) having several compositions were grown by the floating zone melting technique and the distribution of the magnetic properties and Ga contents in the Y3Fe5-xGaxO12system along cross sections parallel and perpendicular to the growth direction were investigated. The preparation of specimens was made on compositions Y3Fe5-xGaxO12, x=0.9,1.0 and 1.2. The pollycrystalline specimen rods, 10mm in diameter and 100mm in length, were crystallized using an apparatus of infrared radiation convergence type. Distribution of saturation magnetization (4πMs) were measured using a magnetic balance. The measurements on ferromagnetic resonance line width (ΔH) were carried out by coupling 0.66mm spheres with transmission line at 4GHz. The results for specimens having Gauss showed that (4πMs) distribution at the core portion along the direction of crystal growth were ±6.9%, whereas within a cut plane perpendicular to the growth direction (4πMs) distribution were ±2.4%. ΔH at the central part was from 0.6-1.0 Oersted. Analysis for gallium was carried out by X-ray microanalyzer and the distribution along the direction of crystal growth was found to be within ±0.34 mo1% against meanvalue.