Efecto del espesor de películas de ferritas de MnZn sobre su respuesta magnética

Thin films were deposited by RF sputtering in oxygen atmosphere of the ferrite dopped with Mn and Zn in the Mn0.5Zn0.5Fe2O4 composition. We investigated their magnetic properties and its dependence with the thickness. Magnetic hysteresis loops were measured by a MOKE system (Magneto-Optical Kerr Effect) at room temperature. A critical grain size was observed, in which the pinning reaches its maximum value, suggesting the change from a monodomain to a multidomain regime. The hysteresis curves were evaluated by a phenomenological model that allows to evaluate the k pinning parameter, which governs such behaviour. A correlation between the size of the superficial structures of the film and the strength of the pinning is suggested.