vibratingsample

Vibrating sample magnetometry (VSM) is a magnetic characterization technique used to measure the magnetic moment of a material by vibrating the sample within a uniform magnetic field and detecting the resulting signal in pickup coils. It is widely used in materials science due to its simplicity and applicability to ferromagnetic, ferrimagnetic, and paramagnetic samples.

Principle: The sample is mounted on a rod attached to an actuator that drives sinusoidal vibrations at a fixed frequency and amplitude. This motion modulates the magnetic flux produced by the sample, inducing an alternating voltage in the pickup coils. The signal, typically read with a lock-in amplifier at the vibration frequency, is proportional to the magnetic moment times the coil geometry. By sweeping the applied field, M(H) hysteresis curves are obtained.

Instrumentation: A typical VSM setup includes a magnet, a vibration system, pickup coils, signal conditioning, and temperature control. Frequencies are usually a few hertz to a few tens of hertz, with small vibration amplitudes to keep detection linear. Background signals from the sample holder are minimized by design and shielding. Measurements can be performed from room temperature to cryogenic conditions.

Applications and interpretation: VSM yields saturation magnetization, coercivity, remanence, and anisotropy for powders, thin films, nanoparticles, and small crystals. It offers non-contact measurement and a wide dynamic range, but requires careful subtraction of background signals and control of mechanical noise for weak signals.

The term vibratingsample is often used interchangeably with vibrational magnetometry in literature and practice.