Homogeneity of YGaIG single crystal grown by the FZ method

Abstract

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 Y 3 Fe 5-x Ga x O 12 system along cross sections parallel and perpendicular to the growth direction were investigated. The preparation of specimens was made on compositions Y 3 Fe 5-x Ga x O 12 , 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 (4πM s ) 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 4\piM_{s}\simeq600 Gauss showed that (4πM s ) distribution at the core portion along the direction of crystal growth were ±6.9%, whereas within a cut plane perpendicular to the growth direction (4πM s ) 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.