Behavior of Magnetic Aftereffect Along a Magnetization Reversal Curve in a Metal Particle Recording Material

Abstract

Experimental measurements of the aftereffect along a magnetization reversal curve are compared with the predictions of a Preisach-Arrhenius model for a high density particulate recording medium. The Preisach parameters are determined from the measurement of the major hysteresis loop and the remanence loop. The Arrhenius parameters were determined from a single aftereffect curve. It was then found that the model gives good qualitative agreement with both the initial slope and, for the case in which the aftereffect is not monotonic, the peak value of the aftereffect.

Magnetic and anomalous magnetic viscosity in the bulk amorphous ferromagnet and partially amorphous ferromagnet

“…Anomalous magnetic viscosity was initially observed in a meltspun Nd 4 Fe 77 B 19 magnet [4] and metal particle thin film recording material [5], but the effect is small, and its study was inhibited, to some extent, by the limited sample mass possible from glassy metal ribbons or thin films, even when coupled with the most sensitive SQUID magnetometer. More recently anomalous magnetic viscosity has been observed in the bulk amorphous ferromagnets Nd 60 Fe 30 Al 10 [6,7] and Nd 60 Fe 20 Co 10 Al 10 [8].…”

Studies on magnetic aftereffect of Fe3O4 nano-particles

“…In fact the non-monotonic phenomenon should be a common property of double-field process, but it is almost impossible or very difficult to be observed experimentally due to the magnetic field control and the accuracy of the measuring time. This phenomenon has been measured in metal particle tape [16]. In this paper, it pointed out that when H 2 less than −100 mT the observed slope of the magnetization -ln t curves was always negative, and for H 2 greater than −80 mT, the slope was always positive.…”

Preisach-Arrhenius model for thermal aftereffect

“…Therefore, the Preisach function is proportional to . For these noninteracting hysterons, , and (6) becomes (12) Thus, (13) when , then , and…”

“…Another experimental verification [13] of the PA model considers the following protocol: Start from positive saturation, then apply a field equal to the negative coercivity, and finally reduce the field to zero. The aftereffect would then start from zero magnetization, rise to a positive magnetization, and finally return to zero.…”