Molecular beam epitaxial growth and characterizations of Co-Mn-Ge Heusler thin films

摘要

We report on the growth of Co-Mn-Ge thin films on various substrates using low-temperature molecular beam epitaxy. The magnetic and transport properties of the films were investigated. The close-to-stoichiometric Co_2MnGe film grown on GaAs(100) shows ferromagnetism and exhibits anomalous Hall effects at room temperature. The irreversibility of zero-field-cooled and field-cooled measurements suggests the formation of superparamagnetic clusters. On the other hand, the growth of Co_2MnGe films on Ge buffer layer and Si(100) substrate is found to be unsuitable due to the degraded crystal qualities with weak magnetization signals.