Lorentz microscopy and small-angle electron diffraction study of magnetic textures in La${}_{1-x}$Sr${}_x$MnO${}_3$ (0.15 $<x<$ 0.30): the role of magnetic anisotropy

Magnetic textures in the ferromagnetic phases of La${}_{1-x}$Sr${}_x$MnO${}_3$ for 0.15 $<x<$ 0.30 have been investigated by Lorentz microscopy combined with small-angle electron diffraction experiments. Various types of magnetic textures characterized by stripe, plate-shaped, and cylindrical (magnetic bubble) domains were found. Two distinct types of magnetic stripe domains appeared in the orthorhombic structure with an inversion symmetry of La${}_{0.825}$Sr${}_{0.175}$MnO${}_3$, depending significantly on magnetocrystalline anisotropy. Based on in-situ observations as functions of temperature and the strength of the external magnetic field, a magnetic field-temperature phase diagram was constructed, showing the stabilization of magnetic bubbles in the ferromagnetic phase of La${}_{0.825}$Sr${}_{0.175}$MnO${}_3$.