Compact variable-temperature magnetic force microscope with optical access and lateral cantilever positioning

Abstract

We describe a compact design for a variable-temperature magnetic force microscope that incorporates a novel mechanical device for the lateral positioning of a piezoresistive cantilever under the guidance of an external optical microscope. The small size of the instrument makes it possible to perform low-temperature experiments by inserting the probe directly into a liquid-helium storage Dewar or into any open or closed liquid-nitrogen container. Besides convenience, this also means that the cycle time for exchanging tips and∕or samples can be as short as 4 h, including warm-up and cooldown. The probe is long enough to reach the middle of an 8 T superconducting magnet. We present the details of this design and show some results.

Design of a variable temperature scanning force microscope

“…3 A number of research groups have reported on operation of SFMs at low temperatures and in the presence of an external magnetic field utilizing piezoresistive cantilevers, tuning forks, and fiber optic interferometers. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] These systems have been successfully used for AFM and magnetic force microscopy ͑MFM͒ studies. Recently, magnetic resonance force microscopy ͑MRFM͒ has attracted a lot of interest due to its high spin sensitivity ͑down to a single electron spin͒ and potential for excellent spatial resolution.…”

Scanning Hall probe microscopy of a diluted magnetic semiconductor

“…This instrument is a good complement to the scanning probes we have previously developed based on tunneling 5,6 or various forces. [7][8][9] Here we report observations made with our SHPM on Ga 0.94 Mn 0.06 As films grown by MBE.…”

“…In the past we have used a breakable seal at the top of the probe, which is always at room temperature. [7][8][9] This is very reliable and does not use up space in the low temperature portion of the apparatus, which is usually very limited. The main disadvantage of such a design is that it is difficult to get a good thermal contact to the cryogenic liquid, so that the temperature of probe may end up a few degrees above that of the bath.…”

A Review of Metrology for Nanoelectronics

“…This is possible by developing variable temperature, otherwise known as low temperature magnetic field microscopy (developed by de Lozanne [25] among others). While the heart of such an instrument is still a microfabricated piezoresistive cantilever sensor, there are four substantial improvements: in situ lateral positioning of the cantilever tip over the sample, external optical access to aid in positioning, a longer probe in order to reach a superconducting magnet inside a standard Dewar, and a better heat sink to allow the MFM to reach lower temperatures.…”