The Modulated Magnetic Domain Structure in the La_0.67Sr_0.33MnO₃ Ferromagnetic Films by Strain Engineering

Novel magnetic domain structures attract much attention due to their potential applications in the high performance of spintronic devices. Herein, the magnetic domains of La_0.67Sr_0.33MnO₃ (LSMO) thin films, which epitaxially grown on (100)-, (110)-, and (111)-oriented (LaAlO₃)_0.3(Sr₂AlTaO₆)_0.7 (LSAT) substrates, are systematically investigated. The (100)- and (110)-LSMO films show a stripe domain pattern. After in-plane magnetic field saturation, the direction of the stripe domains in (100)-LSMO no longer rotates with the change of magnetic field, while the stripe domains in (110)-LSMO rotate continuously. The (111)-LSMO films produce randomly distributed bubble-like magnetic domains, which gradually connect into strips with the increase of the external magnetic field, and the stability of the magnetic domain in (111)-LSMO is better than the ones in (100)- and (110)-LSMO under a magnetic field. In addition, it is found that with the increase of thickness, the random domains in (111)-LSMO films are gradually transformed into mazy domains. These phenomena can be understood by the regulable strain anisotropy and the magnetic anisotropy. Herein, an effective way is suggested to modify the magnetization anisotropy and magnetic domain because spin polarization depends strongly on the crystal surface orientation as well as epitaxial strain.