Multifunctional atomic force microscope cantilevers with Lorentz force actuation and self-heating capability


Somnath S., Liu J. O., Bakir M., Prater C. B., King W. P.

Nanotechnology, vol.25, no.39, 2014 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 25 Issue: 39
  • Publication Date: 2014
  • Doi Number: 10.1088/0957-4484/25/39/395501
  • Journal Name: Nanotechnology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: atomic force microscope (AFM), heated cantilever, Lorentz force, magnetic actuation, tapping-mode AFM, thermal topography imaging
  • Ankara Yıldırım Beyazıt University Affiliated: No

Abstract

This paper reports the development of microcantilevers capable of self-heating and Lorentz-force actuation, and demonstrates applications to thermal topography imaging. Electrical current passing through a U-shaped cantilever in the presence of a magnetic field induces a Lorentz force on the cantilever free end, resulting in cantilever actuation. This same current flowing through a resistive heater induces a controllable temperature increase. We present cantilevers designed for large actuation forces for a given cantilever temperature increase. We analyze the designs of two new cantilevers, along with a legacy cantilever design. The cantilevers are designed to have a spring constant of about 1.5 N m-1, a resonant frequency near 100 kHz, and self-heating capability with temperature controllable over the range 25-600 °C. Compared to previous reports on self-heating cantilevers, the Lorentz-thermal cantilevers generate up to seven times as much Lorentz force and two times as much oscillation amplitude. When used for thermal topography imaging, the Lorentz-thermal cantilevers can measure topography with a vertical resolution of 0.2 nm.