Head field intensity effects on magnetization of sputtered longitudinal media

The effects of thin-film heads having high-saturation magnetization pole pieces on the write characteristics of sputtered thin-film media are studied. Two types of thin-film heads having pole pieces with different levels of saturation magnetization, 1.3 and 1.0 T, are used. The overwrite and noise of various sputtered media having almost the same magnetic properties, such as coercivity and saturation magnetization, are measured by these two heads. The overwrite measured with the 1.3-T head has a value of about 34 dB. However, the overwrite measured with the 1.0-T head having a structure identical to that of the 1.3-T head is found to vary from 20 to 30 dB. On the basis of measurements of media noise as a function of write-field intensity, it becomes clear that the magnetization conditions before signal supply affect the subsequent write characteristics of the sputtered media. Head-field intensity improvement with the use of high-saturation magnetization materials is shown to provide uniform magnetization, leading to improved overwrite characteristics and decreased media noise