Readings

All readings are sections from the course textbook - O’Handley, R. C. Modern Magnetic Materials, Principles and Applications. New York: John Wiley and Sons, 1999. ISBN: 9780471155669.

LEC # TOPICS READINGS
1

Introduction

Course Ground Rules and Overview

Approach: Microscopic to Macroscopic, Impact of Magnetism on Technology (Power, Recording, Magneto-mechanical, Transportation, Security, Sensors, Actuators), Basic Scientific Questions in Magnetism

1.2, 1.3.2, 1.4, 1.4.3, 1.5, 1.6.1
Classical Magnetism
2

Magnetostatics

Origin of Magnetic Fields in and about Magnetized Materials

Maxwell’s Equations Give Boundary Conditions on B and H

2.1-2.4
3

Magnetostatics (cont.)

Demagnetization Factors

Quantitative Magnetostatics and Fields Due to Periodic Domains

2.6
4

Where Do Magnetic Moments Come From?

Classical Free Electron Theory of Magnetism

Orbital Gyromagnetic Ratio

Diamagnetism, Paramagnetism

3.1-3.3, 3.4-3.5 (light), 3.5.2
Quantum Mechanics and Magnetism in Oxides and Metals
5

Spin, Anomalous Zeeman Effect, and Ferromagnetism

Spin Quantum Numbers: l, s, j

Gyromagnetic Ratios for Orbital and Spin Moments

Quantum Theory of Paramagnetism

Extend Quantum Paramagnet via Graphical and Analytic Solution for Brillouin Function for Ferromagnetism

3.5.3, 3.6 (skip 3.6.1, 3.6.2), 3.7.1, 3.7.2
6

Exchange in Insulators

Quantum Origin of Magnetism

Intra-atomic, Hund’s Rules

Superexchange, in Oxides, Internal Pressure of Magnetism

4.1 (concepts), Fig. 4.3, 4.1.6, 4.2, 4.3, 4.4
7

Bonding and Magnetism

Molecular Orbitals in Metals

Slater Pauling Curves, Curie Temperature

Band Theories of Magnetism

5.1, 5.2, 5.3 (partial), 5.4-5.6
Magnetic Energies
8

Magnetic Anisotropy

Magnetic Anistropy Data, Energy to Magnetize, Phenomenology

Ingredients of Magnetic Anisotropy

Anisotropy in Metals and Insulators, Temperature Dependence

6.1, 6.2, 6.3 (concepts), 6.4(concepts), 6.5 (refer to 2.5)
9

Torque Measurement of Magnetic Anisotropy

Observations of Magnetostriction, Macroscopic Phenomenology, Data for Metals and Oxides

7.1, 7.2  (some quant.), 7.3, 7.4 (concepts)
10

Magnetoelastic Anisotropy

Influence of Stress on Magnetization

Temperature Dependence

Measurement Techniques

7.5-7.6 (concept), 7.7

Appendix 7A (summary of Zeeman, anisotropy)

11

Magnetic Domain Walls and Domains

Exchange Energy, Width and Energy Density of Domain Walls

Bloch vs. Néel Walls

8.1, 8.2, 8.3.2, 8.4, 8.5, 8.5.1
12

Magnetic Domains

Magnetic Domains, Closure Domains, Domains in Thin Films and Fine Particles

Single Domain Particles, Superparamagnetism

8.6, 8.7
13

Lab Experience

M-H Hysteresis Loops using Vibrating Sample Magnetometer (VSM)

Magnetization versus Field and Temperature using VSM

Torque Curves for Magnetic Anisotropy using Torque Magnetometer

14 Analysis and Discussion of Lab Results

15

Magnetization Processes

Macroscopic Quasistatic Approach: Applied Field, Anisotropy, Magneostriction, and Dipole Energies

Euler Equations and Boundary Conditions to Calculate Reversible Rotation

Emphasize How Anisotropy, Magnetostriction, Resistivity affect Soft Magnetic Behavior

Microwave Magnetism Ferromagnetic Resoanance

9.1, 9.2, 9.3.1 -9.3.3, 9.4 (qualitative), 9.5
16 Written Mid-term Exam

Magnetic Materials and Applications
17

Soft Ferromagnetic Materials Behavior

Soft Ferromagnetic Materials Behavior, Si-Fe, Fe-Ni, Fe-Co Alloys and Soft Ferrites

Amorphous and Nanocrystalline Alloys

DC Rotation Permeability, Irreversible Rotation

AC Behavior, Skin Depth, Applications

Hysteresis Loss and Eddy Current Loss

10.1-10.6
18

Amorphous Magnetism

Amorphous Magnetism, Competing Interactions

Exchange Fluctuations, Random Anisotropy, Resistivity

Models of Amorphous Magnetism, Alloy Effects vs. Disorder

11.1, 11.2, 11.4.1, 11.4.3, 11.5
19

Nanocrystalline Magnetic Materials

Exchange Fluctuations, Random Anisotropy Effects on Properties with Length Scale

12.1-12.3
20

Hard Magnetic Materials

_M-H, B-H, (B-H)_max, Fine Particles, Nucleation, Pinning

Materials: Alnico, Ba Ferrite, Co-RE, Fe-RE-B

13.1, 13.2 (concept), 13.4, 13.5
21

Transport in Magnetic Materials

Electrical Conductivity of Metals and Alloys in Light of Electronic Structure

Hall Effect and Magnetoresistance (MR), MR Heads, Mechanisms of Spin Scattering, Giant MR, Spin Tunneling

15.1-15.6, 15.7 (concept)
22

Surface and Thin Film Magnetism

Surface Electronic Structure and Magnetism, Surface Moments, Metastable Phases, Misfit Strain, Epitaxial Growth, Surface Magnetic Anisotropy and Magnetostriction, Domains, Devices

16.1-16.4
23

Magnetic Recording

Physics of Recording

Basic Concepts of Recording Media and Heads, Karlkvist Fields, Noise

17.1-17.4
24

Magnetic Recording Materials

Particulate: y Fe2O3 CrO2, Co-Ferric Oxide, Barium Ferrite

Thin Film Media: Longitudinal, Perpendicular

Thin Film Heads, MR Heads, Spin Valves, Magnetic Random Access Memories

17.5-17.6
25-26 Oral Presentations by Students (20-30 minutes)

Course Info

Learning Resource Types

assignment_turned_in Problem Sets with Solutions
grading Exams with Solutions