  Here, we report the origin of magnetic anisotropy in Sr-doped infinite layer
manganites $La_{(1\-x)}Sr_{x}MnO_{3}$ (0.125 \leq x \leq 0.400). Magnetic
anisotropy is responsible for the large difference in the temperature
dependence of field-cooled and zero-field-cooled magnetization. Translational
symmetry breaking in the context of spins around the boundary between the
ferromagnetic (FM) antiferromagnetic (AFM) region leads to FM-AFM interaction
and results in magnetic anisotropy (exchange anisotropy). Here, we propose that
FM-AFM interaction around the boundary between FM clusters or domains in the
AFM background or between AFM clusters or domains in the ferromagnetic
background is responsible for doping-dependent nonmonotonic behavior and the
origin of magnetic anisotropy.
