Possible influence of the ferromagnetic/antiferromagnetic interface on the effective critical behavior of bilayers based on La1−xSrxMnO3

In this work, the effective critical exponent of the spontaneous magnetization, β, and the transition temperature, TC, were calculated from magnetization measurements of three bilayers based on La1−xSrxMnO3 (LSMO). The bilayers structure is a ferromagnetic (FM) LSMO film grown on top of an antiferromagnetic (AF) LSMO film. The value of the antiferromagnetic film thickness was kept the same for the three samples, while the ferromagnetic film had different thickness for each bilayer. Applying a method of calculation based on a linear superposition of the magnetization close to the critical temperature, a β value corresponding to the 3D Ising model was found for the bilayer with the thinnest ferromagnetic film. This result, and the other obtained values are explained taking into account the possible influence of the FM/AF interface on the magnetic and crystal orderings.