Basics Of Ferromagnetism

In this chapter we discuss the effect of nanostructuie on the properties of ferro-magnets, and how the size of nanograms that make up bulk magnet materials affects ferromagnetic properties. We will examine how control of nanoparticle size can be used to design magnetic materials for various applications. In order to understand the role of nanostructure on ferromagnetism, we will present a brief overview of the properties of ferromagnets. In Chapter 4 we saw that certain atoms whose energy...

Introduction To Nanotechnology

Copyright 2003 by John Wiley & Sons, Inc. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the...

Nanostructures In Zeolite Cages

An example of the efficacy of thermoluminescence to provide information on nanostructures is provided by studies of cadmium sulfide (CdS) clusters introduced into the cages of zeolite-Y. This material, which is found in nature as the mineral faujasite (Na2,CaXAl2S 4)Oi2 8H20, is cubic in structure with lattice constant a 2.474 nm. It has a porous network of silicate (S O4) and alum nate (AIO4) tetrahedra that form cube-octahedral cages 0.5nm in diameter, called sodalite cages, since they...

Dynamics Of Nanomagnets

The study of magnetic materials, particularly of films made of nanomagnets, sometimes called mesoscopic magnetism, is driven by the desire to increase storage space on magnetic storage devices such as hard drives in computers. The basic information Figure 7.6. Dependence of the coercive field fit (i.e., hQ on the granular particle size d of a Nd-B-Fe permanent magnet. Adapted from A. Manaf et al., J. Magn. Magn. Mater. 101, 360(1991). Figure 7.6. Dependence of the coercive field fit (i.e., hQ...

When Atoms From The Lattice The Discrete Energy Levels Of The Atom Asre Smduged

One obvious property that will be different is the electronic structure. Table 4.1 gives the result of density functional calculations of some of the electronic properties of A1i3. Notice that binding energy per atom in A1i3 is less than in the bulk aluminum. The Al13 cluster has an unpaired electron in the outer shell. The addition of an electron to form Al 3(-) closes the shell with a significant increase in the binding energy. The molecular orbital approach is also...

Insulator

Illustration of the concept of a computer switching device made from carbon nanotubes. Adapted from C. M. Lieber, Sd. Am., 59 Sept. 2001 . Another idea that is being pursued is to make a computer out of carbon nanotubes. The computer would be an array of parallel nanotubes on a substrate. Above this, but not touching the lower array and having a small separation from them, are carbon nanotubes tubes oriented perpendicular to the tubes on the substrate. Each tube would be connected...

C W 7 o

Bcc Tetrahedral Site

The five Bravais lattices that occur in two dimensions, with the unit cells indicated a square b primitive rectangular c centered rectangular d hexagonal e oblique. Figure 2.2. Sketch of a two-dimensional crystal structure based on a primitive rectangular lattice containing two diatomic molecules A-B in each unit cell. A crystal structure is formed by associating with a lattice a regular arrangement of atoms or molecules. Figure 2.2 presents a two-dimensional crystal structure based...