A VSM operates by first placing the sample to be studied in a constant magnetic field. If the
sample is magnetic, this constant magnetic field will magnetize the sample by aligning the
magnetic domains, or the individual magnetic spins, with the field. The stronger the constant
field, the larger the magnetization will be. The magnetic dipole moment of the sample will
create a magnetic field around the sample, sometimes called the magnetic stray field. As the
sample is moved up and down, this magnetic stray field is changing as a function of time and
can be sensed by a set of pick-up coils.