Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 29: Magnetic Measuring Methods / Sensors / Actuators

MA 29.5: Vortrag

Donnerstag, 29. März 2007, 16:15–16:30, H5

High field cryogen free vibrating sample magnetometer — •Jeremy Good — 30 Acton Park Industrial Estate, London W3 7QE

Cryogenic Ltd. have extended their expertise in Cryogen Free Technology to the development of a High Field Vibrating Sample Magnetometer (VSM). The VSM allows measurements of the DC magnetic moment or AC magnetic susceptibility of a sample. Sensitivity is to 10-6 emu with a suitable averaging time. The standard temperature range is 1.6K to 325K with fields up to 18 Tesla. The VSM measures the magnetic moment by moving the sample between two pick-up coils at a frequency of 1 to 100Hz. As the sample moves into one of the coils, the flux through this coil increases and an e.m.f is generated.

It is now possible to operate the VSM without requiring expensive liquid helium to cool down the magnet and the insert. We offer a choice of cryocoolers with cooling powers to suit the application. The Gifford McMahon (GM) cycle cryocooler has the advantage of a greater thermodynamic efficiency and reliable operation in any orientation. The pulse-tube (PM) cryocooler is quieter, has a longer service interval and low servicing costs, but must operate in the vertical mode only.