Electronic structure and magnetic properties of Ni1-xMnxAl alloys

XPS, magnetization and magnetic susceptibility measurements of Ni1-xMnxAl (x = 0.0, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8) alloys are reported. X-ray diffraction measurements showed that all investigated alloys are single phases with the same CsCl structure type. The hybridization between Al 3sp and Ni 3d states and Al 3sp and Mn 3d states leads to a partial filling of the Ni and Mn 3d bands. Like in the parent compound NiAl, the Anderson condition for the existence of a local magnetic moment on Ni site in Ni1-xMnxAl is not fulfilled. The contribution of Ni atoms to the measured magnetic susceptibility may be explained in the frame of the self-consistent renormalization theory of spin fluctuations. The ferromagnetic behaviour of the Ni1-xMnxAl alloys (x>0) is due to the interaction of local magnetic moments confined on Mn sites. The correlation between the magnetic results in the ordered and paramagnetic state indicates the presence of a number of antiferromagnetically coupled Mn-Mn pairs.