Mechanical and structural properties of Permalloy films on glass and/or Si(111) substrates

Abstract

Permalloy (Py) films were deposited on Si(111) or Corning 0211 glass substrates. There were two deposition temperatures: Ts=room temperature (RT) and Ts=270°C. The film thickness (tf) ranges from 10 to 130 nm. The crystal structure properties of the films were studied by X-ray diffraction and transmission electron microscopy. Mechanical properties (including Young’s modulus Ef and hardness Hf) of each film were measured by the nanoindentation (NI) technique. Ef of the Py/Si(111) films was checked again by the laser induced surface acoustic wave (LA-SAW) technique. It was found that the NI technique is best suited for the measurements of Ef and Hf, but only when the sample belongs to the (soft film)/(soft substrate) system, such as the Py/glass film. For the (soft film)/(hard substrate) system, such as the Py/Si(111) film, the NI technique often provides higher values of Ef and Hf than expected. The anomalous phenomenon, associated with the NI technique may be related to the anisotropic crystal structures in the Py films on different kinds of substrates. From this study, we conclude that [Ef of Py/Si(111)]>[Ef of Py/glass] and [Hf of Py/Si(111)]>[Hf of Py/glass]. The good mechanical properties of the Py/Si(111) film make it a better candidate for recording head applications.