Abstract
Magnetic susceptibility and nuclear magnetic resonance of Al27 and Co59 were studied for Ni–Al, Co–Al, and Fe–Al intermetallic compounds with CsCl-type structure. Curie-Weiss type paramagnetism was observed for the Fe–Al and cobalt rich Co–Al compounds, and Pauli type paramagnetism was observed for the Al rich Co–Al and all Ni–Al compounds. A temperature independent negative Knight shift of Al27 was observed in the Fe–Al system. The line width increases in the Fe–Al and Co–Al compounds when Al content decreases and Curie-Weiss type paramagnetism appears. The line intensity shows a sharp maximum at the stoichiometric composition XAl, and decreases steeply to the both sides due to the effects of quadrupole interactions.
All the results have been discussed based on the band model. It is concluded that the excess Co and Fe atoms make small clusters to which the positive increase in the susceptibility and the line broadening are attributed, and that the vacancies at the Ni and Co sites in the Al-rich sides of the Ni–Al and Co–Al systems produce second-order quadrupole effects on the nearest neighbor aluminum.
