A SENSITIVE AND VERSATILE TORQUE MAGNETOMETER FOR USE IN HIGH MAGNETIC-FIELDS

We describe the design and construction of a sensitive de torque magne tometer 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 magne ts, in particular in the high fields (B approximate to 30 T) produced by Bitter and hybrid magnets. The highest resolution that we have atta ined so far is about 0.3 pNm, which is mainly the result of a symmetri c design. In typical laboratory conditions (at B = 10 T) this correspo nds to a magnetization resolution of about 3 x 10(-11) emu. Other feat ures include modularity, linearity, feedback and forward bias capabili ties, and an in situ calibration of the signal. (C) 1998 American Inst itute of Physics. [S0034-6748(98)05106-5]