Generation of magnetic tape debris and head stain in a linear tape drive

Abstract

The presence of tape debris at the head-tape interface can cause an increase in spacing and consequently an increase in signal loss. In this study, the generation of tape debris in linear tape drives is analysed. Functional drive tests are conducted using thin-film AlO3-TiC and Ni-Zn ferrite heads run against commercial metal particle (MP) tape. Three types of tape debris are found: magnetic particle rich, polymer rich and adherent (stain). Each type is found at a distinct location on the head surface. Optical microscopy and computerized image analysis are used both to quantify the tape debris and to find its distribution on the head. Atomic force microscopy is used to measure the thickness of adherent debris. The Al2O3-TiC sample generates more of all three types than does the Ni-Zn ferrite sample. This is probably a result of the higher hardness of Al2O3-TiC. The differential wear of Al2O3 and TiC probably accounts for the presence of adherent debris on the Al2O3-TiC head. No adherent debris can be found on the Ni-Zn ferrite head. Since the adherent debris collects near the pole tip and is difficult to remove, it potentially poses the greatest head-tape spacing problem, even though its thickness is only of the order of a few nanometres. A relationship is found between the generation of loose debris and the tape speed, tape tension and head wrap. Loose debris generation increases as the tape speed decreases and as the tape tension and head wrap increase. Its generation is found to be approximately proportional to the frictional force. Loose debris, especially the magnetic-particle-rich type, continues to be generated in abundant amounts beyond the burnishing phase for MP tape. The use of an abrasive tape leader is found to reduce the amount of debris at the interface.