The role of lubricants, scanning velocity and operating environment in adhesion, friction and wear of Pt-Ir coated probes for atomic force microscope probe-based ferroelectric recording technology

Probe-based data recording is being developed as an alternative technology for ultrahigh areal density. In potential ferroelectric data storage, a conductive atomic force microscope tip is scanned over a lead zirconate titanate (PZT) film, a ferroelectric material. The understanding and the improvement of wear of the tip during its contact with the ferroelectric materials is critical, particularly at the high scanning velocities needed for high data rate recording in the operating environments. To this end, adhesion, friction and wear experiments are performed using Pt-Ir coated tips sliding against unlubricated and lubricated PZT films at velocities ranging from 0.1 to 100 mm s(-1), the maximum velocity corresponding to the expected recording rate. Two lubricants were used: perfluoropolyether and ionic liquid. The Pt-Ir tips are shown to exhibit lower wear against the lubricated PZT film. To study the role of the operating environment, experiments are also conducted at 80 and 120 degrees C and at 5-80% relative humidity. Relevant wear mechanisms are discussed.