Critical point energies in hcp and fcc cobalt from appearance potential spectra

Abstract

Appearance potential spectra have been measured for (low-temperature) hcp and (high-temperature) fcc cobalt. The measurements allowed a determination of the transition temperatures of (690±6) K for the hcp → fcc transition and (653±12) K for the fcc → hcp transition in good agreement with earlier findings. Critical-point energies are (6.7±0.3) eV for the M point in hcp cobalt and (5.6±0.3) eV for the L7 and (8.9±0.3) eV for the X7, K8 critical points in fcc cobalt, respectively.