Torsion cantilever as magnetic torque sensor

Abstract

High sensitivity magnetic head for a shaft torque sensorA macroscopic cantilever for capacitive torque magnetometry has been developed and tested. It is based on torsion arms in order to obtain better damping against external vibrations than with ordinary cantilevers of similar size but anchored on one side. Microfabricated out of silicon-on-insulator wafers by deep reactive ion etching, the sensor consists of a long ͑14 mm͒ and thin ͑40 m͒ cantilever with two capacitive plates, anchored at its center to a rigid frame by two torsion bars having a rectangular cross section (80ϫ40 m 2 ). By comparing the theoretical and experimental resonance frequencies in three different oscillation modes, we show that the elastic properties of the torque sensor can be evaluated with good accuracy. Calibrations performed with a piece of Fe 2 O 3 audiotape and a cylindrical NdFeB magnet yield a torque sensitivity better than 5 ϫ10 Ϫ13 N m under optimized conditions. This device can also be used as a sensitive Gauss meter to detect magnetic fields down to 10 nT.

Automated operation of a homemade torque magnetometer using LabVIEW

“…The torque sensor with a sample mounted on it is inserted into the cryostat and connected to a Lock-In Amplifier (LIA) for read out. Details of the measurement principle are beyond the scope of this article and are described elsewhere 3,4 . All devices needed to control and measure the system's state are connected to a Windows PC via an IEEE-488 General Purpose Interface Bus (GPIB), RS-232 serial connections and indirectly via additional analog and digital input and output ports present in the LIA instrument.…”

Cantilever torque magnetometry on coordination compounds: from theory to experiments

“…The combination of a cantilever with a magnetic tip allowed even the detection of a single spin [76]. In this review, we will instead focus on capacitive detection: a capacitive (electrical) detection of the deflection of the upper plate of a capacitor (the cantilever) requires an extremely simple and relatively inexpensive experimental set-up, but at the same time assures high sensitivity and fast data acquiring time [77,78].…”

Membrane-based torque magnetometer: Enhanced sensitivity by optical readout of the membrane displacement

“…[1][2][3] The last of these offer high sensitivity and are mostly employed for the study of single crystals or thin films. [4][5][6][7] Torque magnetometry is an important tool in today's condensed matter physics, in particular, in the field of nanomagnetic materials, superconductors, topological insulators, and heavy fermion systems.…”