VibratingSampleMagnetometer

Vibrating Sample Magnetometer (VSM) is a laboratory instrument used to measure the magnetic properties of materials by vibrating a small sample within a uniform magnetic field and detecting the resulting magnetic signal. During operation, the sample is mounted on a nonmagnetic rod attached to a vibrator that moves the sample sinusoidally. The magnetization of the sample induces a time-varying magnetic flux in nearby pickup coils, producing an alternating voltage that is read by a lock-in amplifier. The detected signal is proportional to the component of the sample’s magnetic moment along the vibration axis, allowing determination of magnetization as a function of applied field.

A typical VSM comprises a magnet system to provide a controlled DC field, a vibration mechanism and nonmagnetic sample holder, detection coils arranged to sense the flux change, and electronics with phase-sensitive detection. Many configurations include temperature control or cryogenic equipment to study temperature dependence, enabling measurements from room temperature to cryogenic regimes. Calibration with standard samples converts the output voltage into absolute magnetization units (such as emu or A·m^2).

Applications include obtaining magnetization versus field (M-H) curves to determine saturation magnetization, coercivity, remanence, and magnetic susceptibility. VSMs are widely used for ferromagnetic, ferrimagnetic, and paramagnetic materials, as well as for superconductors and nanomagnetic systems. They offer rapid, non-destructive measurements with reasonably high sensitivity for moderate to large magnetic moments.

Limitations include lower sensitivity compared with SQUID magnetometers for very weakly magnetic samples, potential background signals from the sample holder and environment, and the need for careful calibration and vibration isolation. Signal accuracy depends on field homogeneity, vibration amplitude, and proper normalization.