[材料物理课件8材料磁性性质.ppt

Device configurations Polyaniline nanofiber Gold nanoparticles Organic/nanoparticles system Metal complex Donor Acceptor Donor-Acceptor system Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Performance and Characterization ON/OFF current ratio Write-read-erase cycles Switching time Retention ability Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Nano-crystal floating-gate memory Oxide gate too thin Leakage path Cause electron stored to leak out How to alleviate the scaling limitation? use thinner tunnel oxides without sacrificing nonvolatility oxide thickness operating voltage operating speeds Dielectric Tunnel oxide Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Magnetic Properties of Materials Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. I , Magnetization Curves Fig. MPA a) is the curve in the absence of any material: a vacuum. The gradient of the curve is 4π.10-7 which corresponds to the fundamental physical constant μ0. magnetic flux density : (A/m, Gs) B = μ0 (H + M ). M = χ mH B = μH= μ0 (1+χm)H , μ r= μ/ μ0 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. II, Magnetic moment The concept of magnetic moment is the starting point when discussing the behaviour of magnetic materials within a field. If you place a bar magnet in a field then it will experience a torque or moment tending to align its axis in the direction of the field. A compass needle behaves the same. This torque increases with the strength of the poles and their distance apart. So the value of magnetic moment tells you, in effect, how big a magnet you have. It is also well known that a current carrying loop in a fie