Previous abstract | Graphical version | Text version | Next abstract

Session K9 - Tribology II: Energy Dissipation & Sliding Mechanisms.
MIXED session, Wednesday morning, March 22
102D, MCC

[K9.010] Ultrasensitive Measurements of Vacuum-Mediated Friction and Force Fluctuations

B.C. Stipe, H.J. Mamin, D. Rugar (IBM Research Division, Almaden Research Center), T.D. Stowe, T.W. Kenny (Departments of Applied Physics and Mechanical Engineering, Stanford University)

We report measurements of non-contact friction/force fluctuations between a sample and an AFM cantilever tip. Vacuum-mediated force fluctuations as small as an attonewton/\sqrtHz were directly observed by the real-time thermal (Brownian) motion of the tip. Measurements were made for tip motion parallel to the sample surface with tip-sample separations of 10 to 1000~Åtemperatures of 3 to 300~K, and for various tip and sample materials and bias voltages. For the case of a Au(111) sample and gold-coated tip with zero potential difference, we find friction/force fluctuations approximately 1000 times smaller than previously reported. We interpret our force fluctuations in terms of thermal charge fluctuations interacting with local static inhomogeneous electric fields. The relevance of this work to the detection of a single spin by magnetic resonance force microscopy (MRFM) will be discussed.

Part K of program listing