Paraprocess

Paraprocess 

(also true magnetization), the increase in the absolute value of the spontaneous magnetization J_s of ferromagnetic, ferrimagnetic, and, in the general case, antiferromagnetic substances on exposure to an external magnetic field H. The paraprocess is due to the orientation in H of the elementary carriers of the magnetism (the spin magnetic moments of electrons or the magnetic moments of ions) that are not aligned in the direction of the resultant magnetization because of the disordering action of thermal motion.

The paraprocess follows the processes of technical magnetization and is the final stage of the magnetization of ferromagnetic and ferrimagnetic substances. It is observed in fields whose magnitude exceeds that of the technical magnetic saturation field H_s. As H increases (if H > H_s), J_s approaches the magnitude of absolute saturation J₀—that is, the magnetization that the ferromagnet would have at the absolute zero of temperature. Jo corresponds to the complete ordering of the magnetic moments of the carriers of the magnetism. In most cases, the paraprocess gives only a small increment in the magnetization. For this reason, the magnetization process is considered essentially complete when the technical saturation J_s is reached by a ferromagnetic specimen. Near the Curie point, however, the role of the paraprocess is enhanced because of the greater number of magnetic moments disoriented by the increased thermal motion. In this case, the paraprocess determines almost entirely the character of the magnetization of ferromagnetic and ferrimagnetic substances.

K. P. BELOV