Vibrating Sample Magnetometer (VSM)
The Cryogenic Vibrating Sample Magnetometer (VSM) is designed for measurement of the DC magnetic moment of a sample with a noise floor sensitivity of 10-6 and at 10 seconds integration time.
In order to generate a signal proportional to the magnetic moment, the sample is set to vibrate in a constant (or slowly varying) applied field. The signal is detected by an astatic pair of pick-up coils. The coils sense the variation of magnetic flux due to the sample movement. The pick-up coils are located inside the Variable Temperature Insert (VTI) within the bore of the superconducting magnet. The signal is detected by a lock-in amplifier.
The standard temperature range is 1.6 K to 400 K. Optionally, a sample heater is used to extend the temperature range up to 1000 K.
The magnetometer has an automated gas handling system, and the sample is loaded through an airlock. The VTI can be kept at low temperature during sample exchange, which makes the sample replacement easy and quick.
In the cryogen-free VSM special care is taken to isolate the pick-up system from vibrations generated by the cryocooler. As a consequence, the sensitivity of the cryogen-free systems is as high as in more traditional liquid helium machines.
|Sample temperature range (VTI)
||1.6 – 325K
|Range of the z-axis translation stage
|Maximum sample size
|Optimum sample size
||5mm or smaller
|Noise base (10 sec averaging)
||1 x 10-6 emu
|Dynamic range (standard)
|Accuracy and reproducibility
||2 x 10-6 emu/√Hz +
B x 5 x 10-7 emu / T /√Hz