Study on lattice constant and magnetic properties of bismuth substituted YIG polycrystal thin film on different substrates prepared by rf magnetron sputtering

In this study, we investigated the magnetic and magneto-optical properties of Bi1.5Y1.5Fe5O12 (Bi:YIG) films prepared on quartz and silicon substrates, respectively, by radio frequency magnetron sputtering and disposed by microwave annealing. The results indicated that the lattice constant and magnetic properties were significantly different on different substrates. First, the lattice constant of film on quartz substrate was found to be 9% greater than that on silicon substrate because of larger residual stress. Second, the grain size of film on silicon substrate was smaller than that on quartz substrate at same annealing temperature, which led to its magnetization being 70% smaller than that on quartz substrate and coercive force was 50% less. Finally, the transmittance of the Bi:YIG film and pure YIG was studied and the Faraday angle of Bi1.5Y1.5Fe5O12 film on quartz substrate was found to be − 8°/µm at λ = 544 nm and − 1.8°/µm at λ = 677 nm.