Dipolar Interactions in Superparamagnetic Nano-Granular Magnetic Systems

Autor:	Roy W. Chantrell, M. El-Hilo, J. Al Saei
Rok vydání:	2011
Předmět:	Magnetization Dipole Materials science Ferromagnetism Condensed matter physics Field (physics) Antiferromagnetism Electrical and Electronic Engineering Magnetic hysteresis Magnetic susceptibility Electronic Optical and Magnetic Materials Superparamagnetism
Zdroj:	IEEE Transactions on Magnetics. 47:3362-3365
ISSN:	1941-0069 0018-9464
Popis:	In this paper, the effect of a symmetric distribution of dipolar fields acting along the applied field on the magnetization curve of a superparamagnetic nano-granuler system is examined. The calculations show that the magnetization curves are depressed when the spread of dipolar fields is increased. This reduction in magnetization is attributed to the nonlinear response of magnetization which weighs negative dipolar fields more strongly than the positive dipolar fields. Thus, the reduction in magnetization is not indicative of a predominant negative interaction field, since positive and negative fields are equally probable. Also, for the system examined, the nonlinear response of magnetization is responsible for the predicted negative average ordering temperature in the temperature variation of the initial susceptibility. Thus, in random systems, the interpretation of a negative ordering temperature as antiferromagnetic order, or the positive ordering temperature as a ferromagnetic order should be cautiously stated.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::bc60a9c4ddc1e70b222ce10e8c5c4db8 https://doi.org/10.1109/tmag.2011.2148098 Zobrazit plný text záznamu