Theory of Operation for VSM

WEISTRON Mask Aligner System

A vibrating sample magnetometer (VSM) systems are used to measure the magnetic properties of materials. The vibrating component causes a change in the magnetic field of the sample, which generates an electrical field in a coil based on Faraday’s Law of Induction.

If the sample is placed within a uniform magnetic field H, a magnetization M will be induced in the sample. In a VSM, the sample is placed within suitably placed sensing coils, also held at the desired angle.

And the vibrating sample component is made to undergo sinusoidal motion, i.e., mechanically vibrated.

The hysteresis loop shows the “history dependent” nature of magnetization of a ferromagnetic material. Once the material has been driven to saturation, the magnetizing field can then be dropped to zero and the material will retain most of its magnetization (it remembers its history).


The electromagnet activates before the testing starts so if the sample is magnetic, it will become more so the stronger the field that is produced. A magnetic field H appears around the sample and, once the vibration begins, then the magnetization of the sample can be analyzed as changes occur in relation to the timing of movement. Because magnetic flux changes induce a voltage in the sensing coils that is proportional to the magnetization of the sample. Changes in the signal are converted to values by the software to graph magnetization M versus the magnetic field H strength, often referred to as a hysteresis loop.


Hysteresis Loop


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