Magnetic properties of Y3-xLaxFe5O12 thin films grown by a sol-gel method

Abstract Y 3− x La x Fe 5 O 12 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 magnetic properties and crystalline structures were investigated by using X-ray diffraction (XRD), atomic force microscopy, vibrating sample magnetometer (VSM), and Mossbauer spectroscopy. Films with homogeneous garnet phases were obtained from stock solutions spun on SiO 2 /Si (1 0 0) substrates and fired 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 Y 3− x La x Fe 5 O 12 had only peaks of the garnet structure in case of substituting the concentration x less than 0.75. Those of Y 2 La 1 Fe 5 O 12 consisted of peaks from garnet and LaFeO 3 structures. The microstructure of the films with a square shape consisted of 200–300 nm in size and 5–8 nm in surface roughness. The garnet had the largest saturation magnetization, about 34 emu/cm 3 , and the lowest coercivity, 27 Oe.