['The', 'ferromagnetism', 'of', 'nickel', 'is', 'accounted', 'for', 'by', 'performing', 'all', 'calculations', 'using', 'spin', 'polarization', ',', 'starting', 'at', 'a', 'ferromagnetic', 'initial', 'configuration', 'and', 'relaxing', 'towards', 'its', 'ground', 'state', '.']