Browsing by Author "Hoffmann, P. M."

Now showing items 1-8 of 8

    • Direct measurement of interatomic force gradients using an ultra-low-amplitude atomic force microscope 

      Hoffmann, P. M.; Oral, A.; Grimble, R. A.; Özer, H. Ö.; Jeffery, S.; Pethica, J. B. (The Royal Society Publishing, 2001)
      Interatomic force gradients between a W tip and a 7 × 7 reconstructed Si(111) surface were measured using an off-resonance, ultra-low-amplitude atomic force microscope (AFM) technique. The amplitudes used were less than 1 ...

    • Direct measurement of molecular stiffness and damping in confined water layers 

      Jeffery, S.; Hoffmann, P. M.; Pethica, J. B.; Ramanujan, C.; Özer, H. Ö.; Oral, A. (The American Physical Society, 2004)
      We present direct and linear measurements of the normal stiffness and damping of a confined, few molecule thick water layer. The measurements were obtained by use of a small amplitude (0.36 Å), off-resonance atomic force ...

    • Energy dissipation in atomic force microscopy and atomic loss processes 

      Hoffmann, P. M.; Jeffery, S.; Pethica, J. B.; Özer, H. Ö.; Oral, A. (American Physical Society, 2001)
      Atomic scale dissipation is of great interest in nanomechanics and atomic manipulation. We present dissipation measurements with a linearized, ultrasmall amplitude atomic force microscope which is capable of measuring ...

    • A highly sensitive atomic force microscope for linear measurements of molecular forces in liquids 

      Patil, S.; Matei, G.; Dong, H.; Hoffmann, P. M.; Karaköse, M.; Oral, A. (American Institute of Physics, 2005)
      We describe a highly improved atomic force microscope for quantitative nanomechanical measurements in liquids. The main feature of this microscope is a modified fiber interferometer mounted on a five axis inertial slider ...

    • Linear measurements of nanomechanical phenomena using small-amplitude AFM 

      Hoffmann, P. M.; Patil, S.; Matei, G.; Tanülkü, A.; Grimble, R.; Özer, Ö.; Jeffery, S.; Oral, Ahmet; Pethica, J. (Materials Research Society, 2004)
      Dynamic Atomic Force Microscopy (AFM) is typically performed at amplitudes that are quite large compared to the measured interaction range. This complicates the data interpretation as measurements become highly non-linear. ...

    • Low-amplitude, force gradient imaging of Cu(100) surface using tunnel current feedback 

      Özer, H. Ö.; Norris, A.; Oral, A.; Hoffmann, P. M.; Pethica, J. B. (Institute of Physics Publishing, 2004)
      The large corrugation amplitudes in scanning tunnelling microscope (STM) images of metal surfaces have been commonly attributed to the action of forces between the tip and the sample. We have investigated the Cu(100) surface ...

    • Nanomechanics using an ultra-small amplitude AFM 

      Hoffmann, P. M.; Jeffery, S.; Oral, Ahmet; Grimble, R. A.; Özer, H. Özgür; Pethica, J. B. (Cambridge University Press, 2001)
      A new type of AFM is presented which allows for direct measurements of nanomechanical properties in ultra-high vacuum and liquid environments. The AFM is also capable to atomic-scale imaging of force gradients. This is ...

    • Solid or liquid? Solidification of a nanoconfined liquid under nonequilibrium conditions 

      Patil, S.; Matei, G.; Oral, A.; Hoffmann, P. M. (American Chemical Society, 2006)
      There has been a long-standing debate about the physical state and possible phase transformations of confined liquids. In this report, we show that a model-confined liquid can behave both as a Newtonian liquid with very ...