Study of Magnetization Reversal Processes of Cobalt Nanowires Using NMR and Radiofrequency Resonance Magnetometry Methods

The processes of magnetization reversal of a sample with cobalt nanowires oriented in an external magnetic field in an epoxy matrix have been studied. For this purpose, two complementary methods were used: the microscopic NMR spin-echo method using an additional magnetic videopulse and the macroscopic method of radiofrequency resonance magnetometry. These methods made it possible to obtain information about the coercive force of cobalt nanowires and the pinning force of domain walls in them from the sharp minima of the magnetometer resonance frequency and the thresholds for the decay of the double-pulse echo signal under the influence of a magnetic videopulse, respectively. The hysteresis dependence of the change in NMR resonance frequency with a cyclic change in the longitudinal external magnetic field has been obtained. The estimates of coercive forces and domain boundaries pinning forces in cobalt nanowires in an epoxy matrix are in satisfactory agreement with similar results obtained by other authors with the methods of magnetoresistance measuring.