Magnetism and Magnetic Materials

In this module knowledge of fundamental characteristics of magnetic systems will be acquired. In the introduction there will be a discussion of atomic magnetism, paramagnetism and diamagnetism. Subsequently magnetic order in solid state matter will be introduced. Magnetic phases characterized by long-range order will be discussed and their behavior as a function of temperature and magnetic field will be analyzed. Micromagnetic properties such as domains and domain walls of ferromagnetically ordered systems will be studied. Finally magneto-resistive effects which are important for technological applications will be studied. Several experimental techniques and modern applications of magnetic materials will be presented.

After successful completion of the module the students are able to:

1. Evaluate the response of magnetic materials when applying a magnetic field,
2. Evaluate the magnetic properties of isolated ions and atoms,
3. Understand the influence of a crystallographic environment on ions and atoms,
4. Analyze the magnetic properties of free charge carriers in solids,
5. Understand the various coupling mechanisms between magnetic moments,
6. Understand magnetic ordering and phase transistions, and
7. Analyze the results of experimental data with respect to manifestations of magnetism

No preconditions in addition to the requirements for the Master’s program in Physics.

The module consists of a lecture and exercise classes.

In the thematically structured lecture the learning content is presented. With cross references between different topics the universal concepts in physics are shown. In scientific discussions the students are involved to stimulate their analytic-physics intellectual power.

In the exercise the learning content is deepened and exercised using problem examples and calculations. Thus the students are able to explain and apply the learned physics knowledge independently.

PowerPoint, Board work, Excercise sheets

• S. Blundell: Magnetism in Condensed Matter, Oxford University Press, (2000)
• J.M.D. Coey: Magnetism and Magnetic Materials, Cambridge University Press, (2010)
• R. Skomski: Simple Models of Magnetism, Oxford University Press, (2008)
• J. Stöhr & H.C. Siegmann: Magnetism, Springer, (2006)

There will be an oral exam of 25 minutes duration. Therein the achievement of the competencies given in section learning outcome is tested exemplarily at least to the given cognition level using comprehension questions and sample calculations.

For example an assignment in the exam might be:

• Description of the temperature dependence of a ferromagnetic material in an applied magnetic field and in zero magnetic field
• Derivation of Bloch’s law
• Reason for the formation of magnetic domains
• Description of a magnetic domain wall
• Explanation of the giant magnet-resistance effect
• Origin of oscillatory exchange coupling

In the exam no learning aids are permitted.

Participation in the exercise classes is strongly recommended since the exercises prepare for the problems of the exam and rehearse the specific competencies.