Fluctuation aftereffect in magnetic materials

• Published in: IEEE transactions on magnetics Vol. 35; no. 6; pp. 4407 - 4413
• Main Authors: Street, R., Crew, D.C.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.11.1999; Institute of Electrical and Electronics Engineers
• Subjects: Activation; Activation energy; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Energy distribution; Exact sciences and technology; Fluctuation; Fluctuations; GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; HYSTERESIS; Magnetic anisotropy; Magnetic films; Magnetic hysteresis; MAGNETIC MATERIALS; Magnetic moments; MAGNETIC PROPERTIES; Magnetic properties and materials; Magnetic recording materials; MAGNETIC STORAGE DEVICES; MAGNETIZATION; Magnetization reversal; Metastasis; Perpendicular magnetic anisotropy; Perpendicular magnetic recording; Physics; Studies of specific magnetic materials; TIME DEPENDENCE; Magnetization reversal; Hysteresis loop; Theoretical study; Magnetic hysteresis; Recording material; Magnetic materials; Magnetic aftereffect; Activation energy; Magnetic recording; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/20.809132

Time dependence of magnetization under constant field conditions is exhibited by all materials subject to hysteresis. The phenomenon is a consequence of thermal activation of irreversible magnetization effects from metastable to stable states. Experimental observations of time dependence may be accounted for by considering distributions of the energy required for activation of the metastable states. Two simple cases are considered in this paper. The first involves a fixed value activation energy distribution; the second is concerned with magnetization events that all have the same value of activation energy. The latter is applicable to describing magnetization of magnetooptic films. It is shown that the results of measurements of time dependence of magnetization over wide ranges of time and field are useful in distinguishing between different mechanisms involved in magnetization reversal processes.