title: Multifunctional atomic force microscope cantilevers with Lorentz force actuation and self-heating capability.
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.
authors.affiliation: Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
authors.forename: Suhas
authors.initials: S
authors.lastname: Somnath
authors.forename: Joseph O
authors.initials: JO
authors.lastname: Liu
authors.forename: Mete
authors.initials: M
authors.lastname: Bakir
authors.forename: Craig B
authors.initials: CB
authors.lastname: Prater
authors.forename: William P
authors.initials: WP
authors.lastname: King