Dissertation > Excellent graduate degree dissertation topics show

Micromagnetic study of the magnetic properties of magnetic nanowires

Author: ZhangLaMei
Tutor: GuoGuangHua
School: Central South University
Course: Condensed Matter Physics
Keywords: Nanowires Micromagnetic Magnetization reversal mechanism Coercivity Angle
CLC: TM271
Type: Master's thesis
Year: 2005
Downloads: 299
Quote: 0
Read: Download Dissertation

Abstract


Micromagnetic structure and magnetization reversal mechanism of magnetic nanowires is an important scientific problems , magnetic nanowire arrays future ultra-high density perpendicular magnetic recording media ideal choice . Based on micro - magnetic theory of the magnetic properties of magnetic nanowires following studies : (1 ) aspect ratio are 10 different diameter nanowires magnetization reversal mechanism by means of micromagnetic simulation system found nanowires magnetization reversal mechanism is strongly dependent on the nanowire diameters and diameter very hour reversal mode is consistent reversal, as the diameter increases the inversion mode transition for two different types of magnetization nuclear (uniform cross - section of magnetization of nuclear or vortex the formation and propagation of the magnetization of the spin sectional core) , the reversing process of the larger diameter nanowires by the vortex center of a multi-domain movement to achieve the movement of the center of the scroll to meet the right-hand rule . Magnetization reversal mechanism transition critical dimension . Calculation of the different diameters of nanowires coercive force, the coercive force with the change in the diameter from the angle of the magnetization reversal mechanism explained . (2) Simulation of a variety of defects, and the magnetostatic coupling interaction between the impurities and the nanowire magnetization reversal mechanism and the coercive force of the nanowires , and further explains the reason for the difference of the experimental and theoretical values ??exist . (3) relationship with the change of the angle ( the angle between the external field and the long axis of the nanowire ) simulate the aspect ratios are 10 different diameters of nanowires coercivity Hc ( θ ) . Found Hc (θ) varies with the change in the diameter of the nanowires . When the diameter is smaller than the critical diameter of the nanowires , the coercive force is reduced with increasing angle ; diameter greater than the critical diameter , the coercive force in the middle point of a peak ; as the diameter increases, the coercive force peaks increasing angle , small angle great local phenomenon increasingly weak . From the angle of the reversing mechanism of this phenomenon has been explained , to give the HC ( θ ) corresponding to the magnetization reversal mechanism . (4) the micro - magnetic structure of the multilayer nanowires of different sizes were simulated and found multilayered nanowires There are three possible micro-magnetic structure, gives the ferromagnetic layer thickness to diameter ratio of less than 1 ( T / D ≤ 1) the distribution pattern of the different diameter multilayered nanowires micromagnetic structure . Multilayered nanowires micromagnetic structure will change with the change of the non - magnetic layer thickness .

Related Dissertations

  1. Flow Field Numerical Simulation and Performance Analysis for the Conical Hydrostatic Bearing,TH133.36
  2. Influence of Inclined Secondary Air on Gas-Solid Flows in a W-Shaped Flame Boiler,TK229
  3. Influence of over Fired Air on Gas-Solid Flows in a W-Shaped Flame Boiler,TK229
  4. Influence of Nanostructure on Hydrophobic Properties at TiO2 Surface Studied by Molecular Dynamics Simulation,O614.411
  5. Genetic Segregation Analysis and QTL Mapping as Well as Association Analysis for Panicle Angle Trait in Japonica Rice (Oryza Sativa L.),S511.22
  6. Morphology Control Synthesis and Anode Electrocatalysis Performance of Pt/Pd-based Catalysts for Fuel Cell,TM911.4
  7. Study on Detection System of Deepwater Pipeling Pose Measuring Device,TE973.3
  8. Breeding of Restorer with Erect Pose Panicle and SSR Markers for Alleles of Large Flag Leaf Angle in Japonica Rice (Oryza Sativa L.),S511.22
  9. The Combined Treatment of Complex Adult Angleclass Ⅱ Division 1,R783.5
  10. Genetic Analysis and QTL Mapping for Primary Branch Angle in a Rice (Oryza Sativa L) RIL Population,S511.22
  11. A Prospective Ultrasound Biomicroscopy Evaluation of Changes in Anterior Segment Morphology of Primary Angle Closure after Laser Therapy,R779.63
  12. The Clinical Evaluation of Measuring the Horizontal Sulcus to Sulcus Distance by Ultrasound Biomicroscopy,R770.4
  13. Orthodontic Treatment in Adults with Class Ⅲ Malocclusion Combined Low Angle by Extraction Four Premolars,R783.5
  14. Extraction Orthodontic Treatment of the Low Angle Deep Overbite Malocclusion,R783.5
  15. The Reference Indexes of Clinical Diagnosis Preparation with the Skeletal ClassⅡ Malocclusion in Prepubertal Growth Periods in Dalian,R783.5
  16. Germanium and its oxide nanowire synthesis, characterization and properties of,TB383.1
  17. Experimental Study on Femoral Neck-shaft Projectional Angle Measured by X-ray Estimates Femoral Neck Anteversion and Its Clinical Application,R816.8
  18. A Study of Cephalometric Analysis on Skeletal Calls Ⅱ Malocclusion with High-angle after Tooth-extraction Treatment,R783.5
  19. Preparation of Superhydrophobic Coating and Study of Application,TQ171.68
  20. Research and Implementation on Multi-angle Face Detection Technology Based on Continuous Adaboost Algorithm,TP391.41
  21. Clinical Analysis of the Complications Following Correction of Prominent Mandibular Angle,R622

CLC: > Industrial Technology > Electrotechnical > Electrical materials > Magnetic materials,ferrite > Magnetic materials, ferromagnetic materials
© 2012 www.DissertationTopic.Net  Mobile