Magnetic remanences of gyromagnetic origin in an iron-terbium thin film

The application of an alternating magnetic field at room temperature to a thin film of Tb_0.17Fe_0.83 is shown to produce a remanence of gyromagnetic origin (gyroremanent magnetization-GRM). This is the first time that such an effect has been observed in thin films. The GRM produced appears to have similar characteristics to that acquired by fine particles of single-domain size. A study of GRM in films may help to understand the dynamics of the magnetization response where gyromagnetic effects are important. GRM is the only remanence which, if measured as a function of temperature, is capable of detecting an angular momentum compensation temperature and thus may be of use, for instance, in trying to understand the erase process in single layer direct overwrite magneto-optical recording media since Weng and Kryder have recently proposed that this process may be a consequence of very high wall mobility at the angular momentum compensation temperature