High frequency measurements of CoFeHfO thin films

High-frequency measurements of the transverse susceptibility and damping co nstant of CoFeHfO thin films have been made over a frequency range of 0.1 G Hz to 6 GHz as a function of film resistivity, thickness, and temperature. The film resistivity varied from 250 mu Ohm cm to 2100 mu Ohm cm. The films show relatively low damping at high frequencies with the damping constant a ranging from 0.01 to 0.06. The damping constant increases with film resis tivity and, for the highest resistivity films, the damping constant decreas es as the thickness increases. The damping constant, induced anisotropy, an d film resistivity show weak temperature dependence over a temperature rang e from 4 K to 300 K. The low damping constant, in conjunction with the high anisotropy, large resistivity, and large spin-dependent-tunneling magnetor esistance, makes this material attractive for several high-frequency magnet ic device applications.