Doping Ni80Fe20 by heavy rare earth atoms alters the magnetic relaxation properties of this material drastically. We show that this effect can be well explained by the slow relaxing impurity mechanism. This process is a consequence of the anisotropy of the on site exchange interaction between the 4f magnetic moments and the conduction band. As expected from this model the magnitude of the damping effect scales with the anisotropy of the exchange interaction and increases by an order of magnitude at low temperatures. In addition, our measurements allow us to determine the relaxation time of the 4f electrons as a function of temperature.

No abstract

Articles you may be interested inNanometer-scale imaging of domains in ferroelectric thin films using apertureless near-field scanning optical microscopy Appl.

No abstract

We report on a scanning near-field optical microscope which operates in ultrahigh vacuum and allows magneto-optical Kerr-effect measurements at variable temperatures and in external magnetic fields with subwavelength lateral resolution. High magneto-optical contrast is achieved by combination with a Sagnac interferometer. In this way, magnetic domain patterns of ultrathin films of Fe/Cu(100), grown at 80 K, were studied in situ. A domain phase consisting of perpendicularly magnetized submicron wide stripes with directional order was observed.