Analysis of ferromagnetic removable hard disc media ageing by time of flight-energy elastic recoil detection analysis

Time of flight-energy elastic recoil detection analysis (ToF-E ERDA) has be en applied to study the ageing of commercial thin film hard discs. Samples From a standard commercial removable hard disc were subjected to accelerate d ageing heat treatment in normal humidity from 90 degrees C up to 240 degr ees C in steps of 30 degrees C for 3 h each. A test using a high humidity e nvironment at 90 degrees C up to 40 h was also performed. The ToF-E ERDA was carried out using a 60 MeV I-127(11+) ion beam incident at 67.5 degrees to the surface normal, and detecting recoils at 45 degrees to the ion beam direction by measuring their lime of flight and energy in a detector telescope. The magnetic thin film structure was assigned to be a CNx/Co/N-Cr/Ni-P mult ilayer, At temperatures higher than 180 degrees C the CNx coating layer det oriated with an increase of surface oxygen and an N content reduction in th e N-Cr layer. (C) 2000 Elsevier Science B.V. All rights reserved.