Measuring Permanent Magnets' Properties with Vibrating Sample Magnetometer
Vibrating Sample Magnetometers (VSMs) are the most commonly employed tool for properties measurement of permanent magnet materials. They can be applied to magnet powder, thin films, anisotropic materials, magnetic recording materials, single crystals and liquid, etc.. They also allow for a broad temperature range from 4 K to 1,273 K in which the measured samples are exposed.
VSMs can easily measure the following parameters of a magnetic material: magnetic moment (m), coercivity (Hci), saturation magnetization (Ms), remanence (Mr), energy product (BHmax), etc..
How Do VSMs Work
When a sample is placed inside a uniform magnetic field (In case of the VSM, it is the suitably placed sensing coils), a magnetic moment will be induced and the sample will undergo sinusoidal motion. During the motion magnetic flux changes will occur and voltage will be resulted in the sensing coils, which is proportional to the magnetic moment of the sample but independent of the strength of the applied magnetic field. In a typical system, the voltage id measured by a lock-in amplifier using the piezoelectric signal as its reference signal. Final measuring result is displayed in a hysteresis curve.