Magnetic properties of Ya(3-x)La(x)Fe(5)O(12) thin films grown by a sol-gel method

Y3-xLaxFe5O12 thin films (x = 0.0, 0.5, 0.75) and powder (x = 0.0, 0.25, 0. 5, 0.75 and 1.0) were fabricated by a sol-gel pyrolysis method and their ma gnetic properties and crystalline structures were investigated by using X-r ay diffraction (XRD), atomic force microscopy, vibrating sample magnetomete r (VSM), and Mossbauer spectroscopy. Films with homogeneous garnet phases w ere obtained from stock solutions spun on SiO2/Si (100) substrates and fire d at 873-1073 K for 1 h in air. Results of X-ray diffraction show that the film had no preferred direction. The XRD patterns of Y3-xLaxFe5O12 had only peaks of the garnet structure in case of substituting the concentration x less than 0.75. Those of Y2La1Fe5O12 consisted of peaks from garnet and LaF eO3 structures. The microstructure of the films with a square shape consist ed of 100-300 nm in size and 5-8 nm in surface roughness. The garnet had th e largest saturation magnetization, about 34 cmu/cm(3), and the lowest coer civity, 27 Oe. (C) 2000 Elsevier Science B.V. All rights reserved.