PM-491 Permanent Magnet

When a linear polarization is passed through the material in the magnetic field parallel to the direction of the magnetic field, the polarization plane is rotated. This phenomenon is termed the Faraday effect after the discoverer, which is regarded as optical activity induced by magnetic field.

ORD and CD are used for the observation of the Faraday effect as well as optically active materials. These experiments are named Magnetic Optical Rotary Dispersion (MORD) and Magnetic Circular Dichroism (MCD), respectively, due to phenomenon induced by the magnetic field. Although both the MORD and MCD can be measured by setting the magnet in the sample compartment for the ORD and CD respectively, MCD is widely used today due to simple measurement and high-sensitivity.

Previously, to generate a strong magnetic field over 1 Tesla, a large electrical magnet was used. The electrical magnet cannot be easily set in the sample compartment due to a weight of over 60 kg although it has an advantage that measurements can be performed while changing the intensity of the magnetic field. The PM-491 permanent magnet (small type) can provide a strong magnetic field of 1.6 Tesla. It is also available for the observation of small MCD signals such as a low-concentration sample. In addition, the PM-481 magnet can be easily set in the sample compartment due to its small size. The direction of the magnetic field can be changed by a simple switch to the reverse direction.
MCD is a phenomenon which is observed for all materials in principle. The normal CD spectra provides the configuration and conformational information, whereas the MCD spectra provides the electronic state information.

Measurement examples for neodymium glass, cytochrome C and cobalt chloride (II) 6 hydrate are shown in this technical note.