Observation of microwave-assisted magnetization reversal in perpendicular recording media

Abstract

This letter reports microwave-assisted magnetization reversal (MAMR) in a 700-Gbit/in2 perpendicular media sample. The microwave fields were applied by placing a coplanar waveguide on the media sample and feeding it with narrow microwave pulses. The switching states of the media grains were measured by magnetic force microscopy. For microwaves with a frequency close to the ferromagnetic resonance (FMR) frequency of the media, MAMR was observed for microwave power higher than a certain threshold. For microwaves with certain high power, MAMR was observed for a broad microwave frequency range which covers the FMR frequency and is centered below the FMR frequency.

Near- Tc Ferromagnetic Resonance and Damping in FePt -Based Heat-Assisted Magnetic Recording Media

“…Note also that one can carry out frequency-dependent FMR measurements to determine the inhomogeneity line broadening contribution, as reported in Refs. [33] and [34].…”

Size dependence of magnetization switching and its dispersion of Co/Pt nanodots under the assistance of radio frequency fields

“…15,18,19 While many experimental demonstrations of MAS have been reported so far, most of them are carried out on soft magnetic [20][21][22][23][24][25][26][27] or perpendicular magnetic elements [28][29][30] with the element size as large as several micrometers. Some experiments on granular type perpendicular recording media have been also reported, [31][32][33][34][35] but their switching processes still remain unclear. Very recently, we have carried out the MAS experiments on nanostructured dots of Co/Pt multilayers (Co/Pt in short) with perpendicular magnetic anisotropy.…”

Interlayer Exchange Coupling in Magnetic Hard-Soft Bilayered Structures

“…where is given by (16) The equation used to fit the real and imaginary parts of the experimentally measured complex transmission coefficient S 21 can be written as, where the first term on the right side describes the electronic background, the second denotes the linear electronic drift during the sweeping of the field, and is the usual fitting parameter that has experimental parameters built in. Each term in Eq.…”