A sensitive and versatile torque magnetometer for use in high magnetic fields

We describe the design and construction of a sensitive dc torque magnetometer suitable for liquid as well as solid state samples. It can be used from room temperature down to very low temperatures (mK range) in magnetic fields produced either by superconducting or resistive magnets, in particular in the high fields (B≈30 T) produced by Bitter and hybrid magnets. The highest resolution that we have attained so far is about 0.3 pNm, which is mainly the result of a symmetric design. In typical laboratory conditions (at B=10 T) this corresponds to a magnetization resolution of about 3×10−11 emu. Other features include modularity, linearity, feedback and forward bias capabilities, and an in situ calibration of the signal.