Anisotropic ultrafast spin dynamics in epitaxial cobalt

We investigate the ultrafast spin dynamics in an epitaxial hcp(11¯00) cobalt thin film. By performing pump–probe magneto-optical measurements with magnetization along either easy or hard magnetic axis, we determine demagnetization and recovery time for two axes. observe average of 33% slower which attribute to magneto-crystalline anisotropy electron–phonon coupling, supported by our ab initio calculations. This points toward unambiguous previously undisclosed role anisotropic electron–lattice coupling magnetism.