Q1. Explain what are magnetic anisotropy and its relevance to the magnetic properties of materials. Explain possible selection of magnetic materials according to magnetic anisotropy of the material and related characteristics and their applications, giving examples.
Q2. Explain the tunneling magneto resistance, particularly the simplified relation between the magneto resistance and the magnetic polarization of the materials.
Q3. Explain the phenomenon of super-paramagnetism and discuss the relevance to magnetic applications. In which situations it is desirable/undesirable and how it can be controlled?
Sketch:
a) The temperature dependence of the magnetization measured at low fields and the blocking effects can be observed.
b) The magnetic cycle M versus H above and below the blocking temperature.
Q4. Explain the mechanism of the appearance of mini bands in superlattices. How the miniband width does depend on the barrier thickness?
Q5. Formulate and briefly justify the requirements that electronic quantum dots have to fulfill individually and in ensemble to be used in room temperature devices.