AC susceptometer

I designed a fully automated AC susceptometer in co-operation with Dr. Rudi Hackl (Walter-Meißner-Institut, Garching), which allows to record the magnetic susceptibility of solids (e.g. superconductors) in the temperature range from 3.3 to 320 K. The susceptometer consists of a JANIS SHI-950 two-stage closed-cycle cryostat, a dual-channel temperature controller (Lakeshore 332), a Quantum Design DC transport unit, as well as an EG&G (Signal Recovery) 7260 DSP lock-in amplifier. The coil design, the stepper controller for the transport unit as well as the susceptometer control software (written in LabVIEW) were all developed in-house.

Left image: AC susceptometer; right image: primary and secondary coils after winding

Transport controller, which is based on the dual-channel RN stepper controller by

Some screenshots of the AC susceptometer control software (written in LabVIEW 8.6.1):

Susceptibility measurements of two samples (left: paramagnetic Nd2O3; right: a superconducting iron arsenide):

The LabVIEW stepper controller driver can be downloaded here. Further information is available on request.