The AC Susceptometer option uses a small primary excitation coil to apply an AC field to a sample (typically 1mT at frequencies from 0.1 Hz – 10000 Hz). A pair of secondary pick-up coils positioned close to the excitation coils are used to detect the sample response. The resultant signal is measured using a Lock-In amplifier with the in-phase and out-of-phase components of the signal corresponding to the real and imaginary components of the AC Susceptibility of the sample. An additional compensation coil is used to eliminate background signals.
When bought in conjunction with VSM, the AC Susceptometer shares the same coil set as the VSM enabling immediate change between AC and DC magnetic measurements.
Real and Imaginary parts of magnetic susceptibility, Re(x) and Im(x), as a function of
- applied DC magnetic field
- excitation frequency
- amplitude of excitation field
• Software assisted sample change facility
• Automatic sample centring.
• Automatic pick-up coil compensation to eliminate parasitic signals.
• Shared coil-set with VSM to enable rapid switch between AC and DC magnetic measurements
• User adjustable excitation frequency range.