What Is a Vibrating Sample Magnetometer?

A vibrating sample magnetometer (VSM) is a laboratory instrument for measuring the magnetic properties of a material. 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. By measuring the electrical output, which is amplified in the VSM, a researcher can determine the properties of the material being tested. The vibrating sample magnetometer also includes a device to hold the sample at the desired angle, a vibrating element, a control unit, and a meter. There is also a water supply and a computer with software to collect and analyze the data.

An electromagnet and power supply are also included in a vibrating sample magnetometer. The magnet 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 appears around the material and, once the vibration begins, then the field can be analyzed as changes occur in relation to the timing of movement. The degree of magnetization is determined by software that uses the strength of the field, how fast the sample vibrates, data from a probe that measures the sample’s magnetism, and the value of the magnetic field as a result of vibration. Changes in the signal are converted to values by the software to graph magnetization versus the magnetic field strength, often referred to as a hysteresis curve.

To operate a vibrating sample magnetometer, the sample is mounted onto a rod, and rubber cement is used to secure it. Various components of the system must be turned on in the proper sequence, starting with the water supply, power supply, amplifier, and then the control system. Once the amplifier, electrical meter, and computer are activated, then the software can be loaded and the machine calibrated before the measurement is taken. The functions of the vibrating sample magnetometer when it is operating are controlled using the software interface, which also displays the values as the sample is tested.

There are variations of the components depending on what the vibrating sample magnetometer is used for. In a laboratory, different kinds of electromagnets and varying strength superconducting coils can be integrated depending on the materials tested and the strength of the magnetic field needed. Operators can also use the machine to measure magnetism in relation to temperature and angle in addition to time.