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Micromagnetic exchange coupled hard / soft magnetic multilayers system

Author: LiuZhengFang
Tutor: GuoGuangHua
School: Central South University
Course: Condensed Matter Physics
Keywords: Micromagnetic Remanence Maximum energy product Intrinsic coercivity Exchange coupled multilayer
CLC: TM271
Type: Master's thesis
Year: 2005
Downloads: 183
Quote: 2
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Abstract


Exchange-coupled hard / soft magnetic multilayers system developed in the early 90s of the last century a new structure of magnetic materials, due to its relatively high maximum energy product as well as the potential combination with electronic devices, is expected to become a new generation high-performance magnetic materials. Based on micro-magnetic theory of exchange coupled hard / soft magnetic multilayers the following: (1) based on the the micromagnetic theory developed for analog nanostructures magnet micromagnetic application software. (2) to study the effects of interlayer exchange coupling strength of the magnetic properties, strong and weak on the system's magnetic interlayer coupling can have a dramatic effect, with the interlayer coupling enhancement system remanence and intrinsic coercivity coercive force, a rapid increase in first, then gradually become saturated. (3) study the structural dimensions of exchange-coupled hard / soft magnetic bilayer system, found that: (a) the thickness of the soft layer can have a great impact on the system of magnetic. System remanence first increases with the thickness of the soft magnetic phase, gradually decreases again when the soft magnetic layer reaches a certain thickness. One-dimensional simulation model intrinsic coercivity showed a decreasing trend with the soft phase thickness increase, while the three-dimensional model of the intrinsic coercivity first increases with the increase of the soft magnetic layer thickness, but when the soft magnetic layer reaches a certain thickness , and decreases with the increase in the thickness of the soft magnetic layer. The maximum energy product first with the thickness of the soft magnetic phase increases, gradually decreases again when the soft magnetic layer reaches a certain thickness. (B) the thickness of the hard magnetic layer is on the system magnetic energy but also a certain impact. Remanence and maximum energy product of the system are increased with the thickness of the hard magnetic layer is gradually reduced, but the intrinsic coercive force of the system in the low scales within the scope of the soft magnetic layer, with the thickness of the hard magnetic layer increases, but in the soft magnetic storey scale range, little change. (4) the exchange coupling hard / soft magnetic bilayer membrane system three-dimensional dynamics simulation results show that: when the thickness of the soft magnetic layer is in the critical dimension (a soft magnetic phase and a hard magnetic phase rigorous coupled when the soft magnetic phase size), The hard and soft magnetic layer is achieved through the magnetic moments of rotation in unison. And when the thickness of the soft magnetic layer is greater than the critical size, the plane of the film, the soft magnetic layer having the form of more complex inversion hard magnetic layer the magnetization reversal process is performed by nucleation at the boundary, and then nucleus gradually to the membrane surface center The mobile to achieve its reversal. But also found that certain soft magnetic phase of the thickness of the critical size of the hard magnetic phase. (5) a fixed periodic structure as well as quasi-periodic structure of the total thickness of the hard / soft magnetic exchange coupling multilayers, the number of layers of the system, the magnetic properties of the system can have a great impact. This is certain guiding significance for the preparation of exchange-coupled hard / soft magnetic multilayers.

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CLC: > Industrial Technology > Electrotechnical > Electrical materials > Magnetic materials,ferrite > Magnetic materials, ferromagnetic materials
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