Nanofrictional behavior of amorphous, polycrystalline and textured Y-Cr-O films

Highlights: • Friction coefficient (μ) of ferroelectric textured and polycrystalline YCrO₃ films. • A simple method to evaluate μ from a single AFM image is presented. • The AFM-cantilever spring constant was determined from its dynamic response. • Polycrystalline and amorphous films have a lower μ than textured samples. - Abstract: Differences in friction coefficients (μ) of ferroelectric YCrO₃, textured and polycrystalline films, and non-ferroelectric Y-Cr-O films are analyzed. The friction coefficient was evaluated by atomic force microscopy using a simple quantitative procedure where the dependence of friction force with the applied load is obtained in only one topographical image. A simple code was developed with the MATLAB^® software to analyze the experimental data. The code includes a correction of the hysteresis in the forward and backward scanning directions. The quantification of load exerted on the sample surface was obtained by finite element analysis of the AFM cantilever starting from its experimental dynamic information. The results show that the ferroelectric YCrO₃ film deposited on a Pt(150 nm)/TiO₂(30 nm)/SiO₂/Si (100) substrate is polycrystalline and has a lower friction coefficient than the deposited on SrTiO₃ (110), which is highly textured. From a viewpoint of industrial application in ferroelectric memories, where the writing process is electrical or mechanically achieved by sliding AFM tips on the sample, polycrystalline YCrO₃ films seem to be the best candidates due to their lower μ.