A wide temperature range susceptometer

A new type of high-sensitivity magnetic susceptometer is proposed. It utilises a long thin vibrating wire as a sample support, which is driven at resonance by an alternating field gradient, with no applied dc field. The gradient is generated by a tiny soft ferromagnetic rod close to the sample, The chosen configuration is particularly suitable to perform measurements on thin films and small samples in a wide temperature range (up to 1200 K). A realised prototype for high temperatures is described, with a few examples of measurements. An analysis of the moment sensitivity and considerations on the noise are given, with indications of the physical limits of the technique. A moment sensitivity of the order of 10/sup -11/ A/spl middot/m/sup 2///spl radic/Hz, with an alternating field of 100 A/m, is estimated for the present prototype.