Measurement of the magnetostriction constant of bi-doped garnets by optical observation of stress-induced stripe domains

In this paper, we report on the optical investigation of magnetic microstructures in Bi substituted garnet thin films grown by epitaxial deposition on (111)-oriented gallium gadolinium garnet substrates. The specimens are magnetically diluted with Ga ions. By using a technique based on the bending of the thin film, the appearance of a straight stripe domain pattern is observed. The changes in this stripe pattern due to external applied in-plane and out-of-plane fields are correlated to those induced by a known applied stress. We show that this method can be used to compute the magnetostriction coefficient λ₁₁₁ of the material. One important advantage of this method is that it allows a real-time optical observation of the manifestations of magnetoelastic interactions.