A low-temperature dynamic mode scanning force microscope operating in high magnetic fields

Abstract

A scanning force microscope was implemented operating at temperatures below 4.2K and in magnetic fields up to 8T. Piezoelectric quartz tuning forks were employed for non optical tip-sample distance control in the dynamic operation mode. Fast response was achieved by using a phase-locked loop for driving the mechanical oscillator. Possible applications of this setup for various scanning probe techniques are discussed.

Evaluation of a force sensor based on a quartz tuning fork for operation at low temperatures and ultrahigh vacuum

“…Low-temperature operation of piezoresistive cantilevers has been demonstrated by Volodin and Van Haesendonk [13], and piezoelectric sensors have been operated at low temperature by Rychen et al [14].…”

Atomic resolution on Si(111)-(7×7) by noncontact atomic force microscopy with a force sensor based on a quartz tuning fork

“…The sensitivity S has been calculated and two experimental methods for measuring S have been introduced. The advantages of this sensor over conventional CLs are: ͑i͒ large k allows oscillation with small amplitudes which enhances sensitivity to short-range forces 23 yielding atomic resolution with conventional tungsten tips ͑demonstrated by Erlandsson et al 24 ͒, small A's allow simultaneous STM/AFM; ͑ii͒ piezoelectric detection scheme is easy to implement in adverse environments ͑vacuum, low temperature͒ 16 and has extremely low power …”

“…Tuning forks have been used in scanning probe microscopes before. [9][10][11][12][13][14][15][16][17] However, atomic resolution has not been reported so far.…”

Characterization of atomic force microscope probes at low temperatures

“…In the case of operating the microscope in dynamic mode, the force sensor could then be fixed on a quartz tuning fork. 2,3 At low temperature and under an ultrahigh vacuum, this could make the design of the microscope simpler than in our laser beam deflection setup. Since, on biological samples, the friction force and some specific biochemical interactions are also valuable information, contact mode with the standard cantilever still remains a very interesting method to image the surface.…”