Magnetization reversal in composition-controlled Gd1-xCox ferrimagnetic films close to compensation composition

We report on a model system for micromagnetic studies, i.e., ferrimagnetic Gd1-xCox thin films with controlled composition gradient and, therefore, a controlled magnetization gradient along the film. By employing extraordinary Hall effect measurements and Kerr microscopy, we have studied magnetization reversal and shown that, around compensation, varying magnetization with temperature or composition is equivalent. In particular, the coercive field diverges close to the compensation temperature or close to the compensation interface. The position of the compensation interface is very sensitive to temperature and can be used as a probe of sample heating. (C) 2011 American Institute of Physics. [doi:10.1063/1.3609860]