TY - JOUR
T1 - Magnetic phase transformations of face-centered cubic and hexagonal close-packed Co at zero Kelvin
AU - Saal, James E.
AU - Shang, Shunli
AU - Wang, Yi
AU - Liu, Zi Kui
PY - 2010
Y1 - 2010
N2 - The 0K pressure-induced magnetic phase transformations of face-centered cubic (FCC) and hexagonal close packed (HCP) Co have been examined using first-principles calculations. Issues of fitting an equation of state to the first-principles energy versus volume data points containing a magnetic transformation and comparing to experimental phase equilibria are discussed. It is found that a fitting scheme employing only data where the magnetic moment decreases linearly with volume offers a physically meaningful behavior for the equation of state at metastable volumes. From this fitting, the ferromagnetic to nonmagnetic transformations with increasing pressure at 0K are at 77GPa and 123GPa for FCC and HCP, respectively, and are first order and second order, respectively, on the basis of an unambiguous measure proposed in the paper. In addition to the HCP/FCC structure transformation at 99GPa, another transformation at negative pressures is predicted, at - 31GPa. These results are shown to be consistent with the extrapolations of the experimental pressure-temperature phase diagram to 0K.
AB - The 0K pressure-induced magnetic phase transformations of face-centered cubic (FCC) and hexagonal close packed (HCP) Co have been examined using first-principles calculations. Issues of fitting an equation of state to the first-principles energy versus volume data points containing a magnetic transformation and comparing to experimental phase equilibria are discussed. It is found that a fitting scheme employing only data where the magnetic moment decreases linearly with volume offers a physically meaningful behavior for the equation of state at metastable volumes. From this fitting, the ferromagnetic to nonmagnetic transformations with increasing pressure at 0K are at 77GPa and 123GPa for FCC and HCP, respectively, and are first order and second order, respectively, on the basis of an unambiguous measure proposed in the paper. In addition to the HCP/FCC structure transformation at 99GPa, another transformation at negative pressures is predicted, at - 31GPa. These results are shown to be consistent with the extrapolations of the experimental pressure-temperature phase diagram to 0K.
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U2 - 10.1088/0953-8984/22/9/096006
DO - 10.1088/0953-8984/22/9/096006
M3 - Article
C2 - 21389433
AN - SCOPUS:77149162981
SN - 0953-8984
VL - 22
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 9
M1 - 096006
ER -