ELECTRIC AND MAGNETIC PROPERTIES OF B2 STRUCTURE COMPOUNDS - NIAL, COAL

Electrical resistivity, thermoelectric power, and magnetic susceptibility or magnetization have been measured at room temperature and below on compositions surrounding NiAl (49-51 at. % Al) and CoAl (42-54% Al). The resistivity-composition plots show a minimum near 50 per cent. The slopes of the ρ{variant} vs. composition plots are markedly different on opposite sides of the minimum. The thermoelectric power is n-type with a distinct shoulder at 50 per cent. NiAl is Pauli paramagnetic for all compositions as is CoAl for Al-rich compositions. Co-rich CoAl is ferromagnetic with the magnetization approaching zero at about 50 per cent. These results are used to suggest a qualitative energy band model. The main features of this model are similar to those of Goodenough, i.e. a broad hybrid s-p band and several narrow d-bands formed from transition metal atomic orbitals. © 1969.