X-ray photoelectron spectroscopy and magnetism of Al2MnNi and Al5Mn3Ni2

Abstract

The electronic and magnetic properties of Al2MnNi and Al5Mn3Ni2 alloys, obtained from X–ray photoelectron spectroscopy and magnetic measurements, are reported. The most important feature of the XPS spectra is the well-defined magnetic exchange splitting of about 5 eV of the Mn 3s core levels of both alloys, arising from the exchange interactions between the core hole and open 3d shell, giving a clear evidence of the existence of local moments in the Anderson’s sense confined on Mn sites in Al-Mn-Ni alloys. For both alloys the Mn and Ni 3d bands are filled by more than half, which leads to a ferromagnetic coupling between the neighboring local magnetic moments situated at Mn and Ni sites. By correlating the information from the XPS core level spectra and magnetic measurements in the ordered and paramagnetic states, the magnetic behavior of Al2MnNi and Al5Mn3Ni2 cannot be explained in the picture of ferromagnetic systems with a collinear arrangement of the local magnetic moments. We propose a canted ferromagnetism in the two alloys, which should be verified by further neutron diffraction investigations.