Surface degradation of magnetic properties in manganite thin films proved with magneto-optical techniques in reflection geometry

Magneto-optical techniques in reflection geometry turn out to be a very efficient tool to study the surface magnetism due to their sensitivity to magnetic and chemical variations across the sample depth. The existence of a surface layer of about one to five unit cells with strongly depressed magnetic properties, when compared with the rest of the film, in La2/3Ca1/3MnO3 thin films is shown. These results strongly support previous theoretical predictions as well as recent findings showing the insulating nature of the topmost layers in these materials. (c) 2007 American Institute of Physics.