Microwave/Millimeter-Wave Garnet Films

A buffer liquid phase epitaxy method for lead free flux technology has been used to grow large size garnet single-crystal films. Lu
_2.1
Bi
_0.9
Fe
₅
O
₁₂
(Bi:LuIG) films with excellent lattice match with the Gd
₃
Ga
₅
O
₁₅
(GGG) substrate and superior magnetic and magnetic-optical properties have been obtained by optimizing liquid phase epitaxy (LPE) technology. The saturation magnetization of the film is about 1562 Gs, the Faraday rotation is 1.6 ~ 2.0 deg/μm and the minimum ferromagnetic resonance (FMR) linewidth is 2ΔH = 5.1 Oe. Secondly, the growth of polycrystalline garnet films by radio-frequency (RF) magnetron sputtering has be introduced, and the effects of buffer layer, sputtering parameters and post annealing on the performance of Y
₃
Fe
₅
O
₁₂
(YIG) films have been investigated in details. It will be shown that garnet films with smooth surface and adjustable saturation magnetization can be obtained by using a SiO
₂
buffer layer.