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

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...

Suhas Somnath, Joseph O Liu, Mete Bakir, Craig B Prater and William P King

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