Radiation pressure excitation of a low temperature atomic force/magnetic force microscope for imaging in 4-300 K temperature range

Ümit Çelik; Özgür Karcı; Yiğit Uysallı; H Özgür Özer; Ahmet Oral

doi:10.1063/1.4973819

Radiation pressure excitation of a low temperature atomic force/magnetic force microscope for imaging in 4-300 K temperature range

Rev Sci Instrum. 2017 Jan;88(1):013705. doi: 10.1063/1.4973819.

Authors

Ümit Çelik¹, Özgür Karcı¹, Yiğit Uysallı², H Özgür Özer³, Ahmet Oral²

Affiliations

¹ NanoMagnetics Instruments Ltd., METU Technopolis, 06800 Ankara, Turkey.
² Department of Physics, Middle East Technical University, 06800 Ankara, Turkey.
³ Department of Physics Engineering, İstanbul Technical University, 34469 İstanbul, Turkey.

PMID: 28147654
DOI: 10.1063/1.4973819

Abstract

We describe a novel radiation pressure based cantilever excitation method for imaging in dynamic mode atomic force microscopy (AFM) for the first time. Piezo-excitation is the most common method for cantilever excitation, however it may cause spurious resonance peaks. Therefore, the direct excitation of the cantilever plays a crucial role in AFM imaging. A fiber optic interferometer with a 1310 nm laser was used both for the excitation of the cantilever at the resonance and the deflection measurement of the cantilever in a commercial low temperature atomic force microscope/magnetic force microscope (AFM/MFM) from NanoMagnetics Instruments. The laser power was modulated at the cantilever's resonance frequency by a digital Phase Locked Loop (PLL). The laser beam is typically modulated by ∼500 μW, and ∼141.8 nm_pp oscillation amplitude is obtained in moderate vacuum levels between 4 and 300 K. We have demonstrated the performance of the radiation pressure excitation in AFM/MFM by imaging atomic steps in graphite, magnetic domains in CoPt multilayers between 4 and 300 K and Abrikosov vortex lattice in BSCCO(2212) single crystal at 4 K for the first time.