title: Atomic force acoustic microscopy: Influence of the lateral contact stiffness on the elastic measurements.
abstract: Atomic force acoustic microscopy is a dynamic technique where the resonances of a cantilever, that has its tip in contact with the sample, are used to quantify local elastic properties of surfaces. Since the contact resonance frequencies (CRFs) monotonically increase with the tip-sample contact stiffness, they are used to evaluate the local elastic properties of the surfaces through a suitable contact mechanical model. The CRFs depends on both, normal and lateral contact stiffness, kN and kS respectively, where the last one is taken either as constant (kS<1), or as zero, leading to uncertainty in the estimation of the elastic properties of composite materials. In this work, resonance spectra for free and contact vibration were used in a finite element analysis of cantilevers to show the influence of kS in the resonance curves due to changes in the kS/kN ratio. These curves have regions for the different vibrational modes that are both, strongly and weakly dependent on kS, and they can be used in a selective manner to obtain a precise mapping of elastic properties.
authors.affiliation: Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, km. 107, Carretera Tijuana-Ensenada, 22860 Ensenada, B.C., Mexico; CINVESTAV Unidad Querétaro, Lib. Norponiente 2000, Real de Juriquilla, 76230 Querétaro, Qro., Mexico. Electronic address: fjflores@cnyn.unam.mx.
authors.forename: F J
authors.initials: FJ
authors.lastname: Flores-Ruiz
authors.affiliation: CINVESTAV Unidad Querétaro, Lib. Norponiente 2000, Real de Juriquilla, 76230 Querétaro, Qro., Mexico.
authors.forename: F J
authors.initials: FJ
authors.lastname: Espinoza-Beltrán
authors.affiliation: Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, km. 107, Carretera Tijuana-Ensenada, 22860 Ensenada, B.C., Mexico.
authors.forename: C J
authors.initials: CJ
authors.lastname: Diliegros-Godines
authors.affiliation: Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, km. 107, Carretera Tijuana-Ensenada, 22860 Ensenada, B.C., Mexico.
authors.forename: J M
authors.initials: JM
authors.lastname: Siqueiros
authors.affiliation: CINVESTAV Unidad Querétaro, Lib. Norponiente 2000, Real de Juriquilla, 76230 Querétaro, Qro., Mexico.
authors.forename: A
authors.initials: A
authors.lastname: Herrera-Gómez
keywords: Acoustics; Atomic force microscopy; Beams; Contact stiffness; Flexural vibrations; Ultrasonics; Young’s modulus