Magnetic properties of feroplug material at sub-ambient temperature

The magnetic properties of Feroplug material at low temperatures have been studied by the use of an a.c. Susceptometer. When this material is aged at elevated temperatures, sigma phase is precipitated as one of the transformation products. It is found that the sigma phase in this material exhibits a magnetic response at low temperature and the magnetic transition starts at 130 K. In the temperature range from 78 to 130 K, the a.c. susceptibility increases abruptly with decreasing temperature. This phenomenon is present in all the aged specimens once sigma phase appears. For specimens with the same solution treatment, the a.c. susceptibility value increases as the sigma content in the material increases.