[en] Short communication

[en] The magnetic properties, i.e. magnetization, coercivity and initially perpendicular magnetic anisotropy, of a granular CoCrPt film can be tuned by Ga irradiation, depending on exposure dose. Focused ion beam irradiation is used to generate a periodic pattern of exposed strips which are magnetically soft, separated by magnetically hard unexposed areas. Investigation with magnetic force microscopy and magneto-optical Kerr effect measurements show several stabilization regions of magnetic domain configurations, which are due to strong magnetic coupling between the strips. The magnetic reversal behavior and domain configurations are investigated by micromagnetic simulations and a comparison with the experimental findings is presented

[en] We analyze the magnetic cluster size (MCS) and magnetic cluster size distribution (MCSD) in a variety of perpendicular magnetic recording (PMR) media designs using resonant small angle x-ray scattering at the Co L₃ absorption edge. The different PMR media flavors considered here vary in grain size between 7.5 and 9.5 nm as well as in lateral inter-granular exchange strength, which is controlled via the segregant amount. While for high inter-granular exchange, the MCS increases rapidly for grain sizes below 8.5 nm, we show that for increased amount of segregant with less exchange the MCS remains relatively small, even for grain sizes of 7.5 and 8 nm. However, the MCSD still increases sharply when shrinking grains from 8 to 7.5 nm. We show evidence that recording performance such as signal-to-noise-ratio on the spin stand correlates well with the product of magnetic cluster size and magnetic cluster size distribution