INVESTIGATIONS OF EPITAXIAL GA-YIG(111) FILMS BY BRILLOUIN LIGHT-SCATTERING AND MICROWAVE SPECTROSCOPY

Brillouin light scattering and microwave spectroscopy measurements hav e enabled the room temperature magnetic characteristics of five Y3Fe5- xGaxO12 (111) films with 0 less than or equal to x less than or equal to 0.73 to be obtained. The film thicknesses ranged from 7 to 10 micro ns. The BLS measurements gave stiffness factors ranging from 5.52 to 8 .77.10(-9) Oe.cm(2). This variation is attributed to the occupation by Ga atoms of the A and D sites causing a decrease in J(ad). The values of 4 pi M-s and gamma deduced were in good agreement with those obtai ned by microwave spectroscopy which examined the frequencies of the MS BVW and MSFVW excitations generated by a periodic array of microstrips . 4 pi M-s decreased from 1.740 kG for x = 0 to 0.645 kG for x = 0.73. A cubic anisotropy field H-K of similar to 45 Oe and first and second order uniaxial anisotropy fields H-u1 and H-u2 of similar to-70 and 5 0 Oe respectively were obtained.