Abstract
The electronic structures of the Heusler alloys Co2MnSn, Co2TiSn and Co2TiAl are calculated using the SAPW method. The common properties and characteristics of these three alloys are seen in their band structures. Whether or not the orbital angular momentum is quenched in the three alloys is discussed on the basis of the band structures. For the Co atom in the Co2MnSn, Co2TiSn and Co2TiAl alloys, the orbital angular momentum is expected to contribute to the magnetic moment and the internal magnetic field.