Magnetic properties and recording characteristics of sputtered double-layer γ-Fe2O3disks

This paper presents the results of the investigation of sputtered double-layer γ-Fe2O3films for high density magnetic recording. Double-layer γ-Fe2O3films were prepared in a serial process from the double cycle reactive sputtering of Fe, which contains up to 3 atomic % Co and 5 atomic % Ti, to α-Fe2O3, reduced to Fe3O4and oxidized to γ-Fe2O3. The coercive force of the double-layer γ-Fe2O3film having the squareness ratio of 0.8 and the residual magnetization of 2500 Gauss, can be precisely controlled by the content of Co ion. High recording density feasibility has been experimentally confirmed. The recording density D50is measured as 1,100 bits/mm (27,900 bpi) and overwrite characteristics are 5 dB greater than that of single-layer γ-Fe2O3.