Atomic disorder in Heusler Co 2MnGe measured by anomalous x-ray diffraction

Heusler alloys Co 2MnX, where X is Ge or Si, are predicted by the band theory to be a half-metallic ferromagnets, i.e., metals with all conduction electrons of the same spin state. To date, Heusler alloys have been measured with spin polarizations of 50%-60%, higher than Fe (∼40%), but not a true half metal. Structural defects involving site swapping between the Co and Mn sublattices have been proposed as a mechanism to diminish spin polarization. In this work, we present an anomalous x-ray diffraction measurement on Co 2MnGe to determine antisite disorder in thin films with a high precision. © 2002 American Institute of Physics. © 2002 American Institute of Physics.