Departmental Papers (MEAM)

Document Type


Date of this Version

March 1997


Copyright (1997) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. Reprinted in Applied Physics Letters, Volume 70, Issue 12, March 1997, pages 1548-1550.

NOTE: At the time of publication, author Robert W. Carpick was affiliated with the University of Wisconsin. Currently (June 2007), he is a faculty member in the Department of Mechanical Engineering and Applied Mechanics at the University of Pennsylvania. Publisher URL:


We present a technique to measure the lateral stiffness of the nanometer-sized contact formed between a friction force microscope tip and a sample surface. Since the lateral stiffness of an elastic contact is proportional to the contact radius, this measurement can be used to study the relationship between friction, load, and contact area. As an example, we measure the lateral stiffness of the contact between a silicon nitride tip and muscovite mica in a humid atmosphere (55% relative humidity) as a function of load. Comparison with friction measurements confirms that friction is proportional to contact area and allows determination of the shear strength.


microscopy, friction, shear, measuring methods, surfaces, elasticity, mica, humidity, silicon compounds, atomic force microscopy, sliding friction, shear strength, mechanical contact, mechanical variables measurement



Date Posted: 25 June 2007

This document has been peer reviewed.