Monocrystalline ferrogarnet films with low magnetizations and small magnetic losses

Abstract

Monocrystalline ferro-garnet films of Y3Fe5-xGaxO12 (0,1 ≤ x ≤ 0,6) and Y3-yLayFe5-xGaxO12 (0,17 ≤ x ≤ 0,94; 0,033 ≤ y ≤ 0,161) were grown on gadolinium-gallium garnet (GGG) Gd3Ga5O12 substrates by the method of liquid phase epitaxy. The mixture of Fe2O3, Y2O3, Ga2O3, La2O3 oxides and PbO-B2O3 solvent to prepare the melt solution were used. The (111) orientation substrates of GGG single crystal were round with a diameter of 50,8 mm and a thickness of 0,5 mm. The mismatch between film and substrate crystal lattice parameters increases with increase of substitution degree × in Y3Fe5-xGaxO12 films which leads to mechanical stresses in film. Through the introduction of the large in size La3+ ions into the composition of Y3Fe5- xGaxO12 ferro-garnet films this shortcoming has been corrected. The thicknesses of Y3Fe5- xGaxO12 films did not exceed 5…8 μm and of Y3-yLayFe5-xGaxO12 films they were 20…70 μm. Concentration dependencies of saturation magnetization (4πMs), anisotropy field (Ha) and ferromagnetic resonance (FMR) line width (ΔH) for both film systems were studied. It was found that Y3-yLayFe5-xGaxO12 films in a wide range of × and y substitutions are characterized by low values of saturation magnetization (400 Gs ≤ 4πMs ≤ 1700 Gs), compared to Y3Fe5O12, and narrow FMR lines width (ΔH = 0,4…0,5 Oe).