Contact pressure effects on pole tip recession and head stain in linear digital tape systems

Linear Tape Open (LTO) and Travan5 heads were tested against the exactly similar formulation metal particles tape loaded into appropriate cartridges at a range of controlled environmental conditions. These tape cartridges were produced specifically for this study by the Imation Corp. Optical Microscopy was used to identify the head stains and debris distribution. Atomic force microscopy (AFM) was used to analyse the changes in surface topography of the heads and Auger electron spectroscopy (AES) was employed to analyse the chemical changes on the surface of the heads after up to 5000 passes of tapes. Conventional Fe based stain was seen to form on the heads of each tape format for all conditions with the exception of Travan5 heads at 40 °C and 80% relative humidity (RH) which were covered with much thicker and more extensive polymer based stain. The Travan5 heads showed a much greater propensity to stain than LTO heads. Pole tip recession (PTR) of the LTO heads was lower than Travan5 heads after cycling for the same distance and in the same environment condition. Higher temperature and higher humidity lead to higher PTR in each system. The contact pressure between the LTO head and tape is much lower than the Travan5 system (around one-third) and this the major factor for the reduced stains and lesser PTR value in the LTO system. The reduced contact pressure not only reduces the number of the three-body particles production, but also reduces chemical effects responsible for PTR and stain. X-ray photoelectron spectroscopy (XPS) was used to identify the chemical changes that occurred at the media surface. This showed that in all areas of the tape, the amount of detected Fe had slightly increased, whilst the N signal (an indicator of polymeric binder) had decreased. No significant tape wear occurred in either the LTO or Travan5 systems. The roughness (RMS measured by AFM) of the tape did not change significantly after cycling in either system, with the exception of Travan5 tapes cycled at the 40 °C, 80% RH which showed an increase. The more tape debris present on the Travan5 heads comparing with LTO heads. The results indicate conclusively that reduced contact pressure is responsible for the reduction in both stain and PTR.