Electronic and magnetic structure of RENi₂Mn_x-compounds (RE = rare earth, x = 0, 0.25, 0.5, 0.75, 1, 1.25) with respect to ErNi₂Mn_x

Rare earth (RE) and transition metal (T) compounds are research field since the 1960s. Because of huge magnetocalorical effect and giant magnetostriction the RE-T-compounds are excellent for applications like magnetic cooling or hydrogen storage devices. Besides of that RE-Ni₂-type of alloys are, due to the relatively simple crystal structure and the fact that Ni₂ does not indicate any %behavior with result in an magnetic moment, excellent candidates for studies of magnetic behavior of RE's and their binding partners. The electronic structure of ErNi₂Mn_x (x = 0, 0.25, 0.5, 0.75, 1, 1.25) is characterized by XPS and ResPES, the magnetic structure is investigated by SQUID and PPMS techniques, and resistivity measurements are made. Variation in Mn concentration revealed the position of Mn 3d-states at 1.7 eV. The XPS intensity at 1.7 eV can be correlated with the behavior of the Curie temperature and the resistivity. While similar RENi₂Mn_x-systems, where RE had been replaced by Gd and Tb, highest resistivity, Curie temperature and the highest Mn 3d-valence band state intensity were observed at x = 0.5. ErNi₂Mn_x-system behave different and show the mentioned maxima at x = 1.25.