Read/write characteristics of a Ba-ferrite sputtered disk

Ba-ferrite thin film rigid disks with various c-axis dispersion angle Δθ50and various film thickness have been prepared by rf diode sputtering. Read/write characteristics of Ba-ferrite disks were evaluated by means of ring type Mn-Zn ferrite head. Reproduced wave forms of isolated magnetization transition showed dipulse and dipulse ratio depended on recording current. Dipulse ratio decreased with increase of recording current. PW50( pulse width at half height of reproduced output at low density ) and λ50( recorded wave length at D50)depended on Δθ50of Ba-ferrite thin film and both PW50and λ50increased with increase of Δθ50. Over-write ratio of -31dB has been obtained at 2F of 40 kfrpi. D50of disks with Δθ50of 2.5∼2.8° depended on the film thickness. 88, 95 and 100 kfrpi in D50for the thickness of 0.26, 0.16 and 0.066 μm, respectively, have been ontained with a head with gap length of 0.4 μm.