The purpose of a research School is to provide young scientists the basics in a working field. With this respect interactivity between students and lecturers should be promoted. Thus a key aspect of ESM is the possibility to raise questions during the course of the lectures, interrupting the lecturer. Questions can also be posted anonymously in 'question boxes'. Special sessions for answering these questions are organized, typically 1h every day or two days, during which the lecturers or voluntary students will present in more detail issues raised by the students during the lectures or anonymously through a question-box. Below is a list of questions raised and explained in 2011 (under way). Whenever the answer has been supported by slides, these are or will be made available.
- It was talked about quenched orbital momentum and how to calculate g value. You said it is possible to use the Berry phase to do this. Please explain.
- Where does Zeeman energy come from?
- Can you describe with simple words (no equation, no scheme) what is the susceptibility?
- What is the hopping energy?
- Re-explain Fermi liquid theory in relation to heavy fermion systems.
- Elaborate on the two paramagnetism (Curie and Pauli) for localized and itinerant magnetism. Is it possible to observe and separate the two effects in the same sample?
- Can you explain how to convert from cgs to SI units? Download a table for converting units provided by S. Blundell (see: http://users.ox.ac.uk/~sjb/magnetism/units.html).
- How does magnon density change around Tc? How magnetic anisotropy affects magnon density? How to experimentally excite magnons and detect their density?
- What is the physical meaning of the Brillouin function?
- Could you explain the hopping mechanism in detail?
- Which are the factors determining a phase transition to be of first order or second order?
- What is chirality?
- Dipolar interactions. Explained by Brendan O'Dowd [ Slides ]
- Please explain intra and inter particle interactions in nanoparticles.
- How are these interactions affected when in a polymer matrix?
- Please explain how to find out information about these interactions from magnetic measurements, on some example.
- In these systems (nanoparticles embedded in polymer matrix) if we observe change in shape of hysteresis loop, how to relate it to the intra-inter particle interactions?
- From the Landau free energy, how to get the thermodynamic free energy?
- Dzyaloshinkii Moriya interaction. Explain the interaction in detail. Are there experimental techniques to measure the nearest neighbor DM vectors?
- What are skyrmions? Is it possible to control skyrmions by current (electron-skyrmion scattering)? Exists there other external control parameters? Do skyrmions have a characteristic dispersion relation? In which materials skyrmions could in principle exist?
- Superparamagnetism is depending on time of measurement. Which are the typical times on different measurement techniques. Squid (100s?) Kerr/Daraday rotation? Mössbauer? Synchrotron radiation (XMCD?) How to correct 25kbT term for these other techniques?
- Can you tell us something about spin waves in metals? (equations are OK)
- Are there any difference between spin wave and spin density waves?
- From all the metals presented in the lectures until now I can't argue why and how transition metals like Mn and Cr choose an antiferromagnetic ordering. Could you shed a light on this mystery?
- Domains in ferromagnets come from the competition of long-range interaction and exchange. How comes there can be domains in antiferromagnets? I am especially interested in thin metallic films systems.
- In the Anderson impurity model (...) are c and f commuting operators? Do these operators describe different types of particles?
- Summarize what are the requirements for a material to show a magnetocaloric effect. Answer by O. Isnard [ Slides ]
- Are terms "magnetic anisotropy" and "magnetocrystalline anisotropy" equivalent?
- Can you please explain why some elements show an in-plane and out-of-plane magnetization which depends on the film thickness?
- Question about spin fluctuations in real and reciprocal space, especially in weak ferromagnets
- To illustrate the vortex core reversal, could you please show us a field sequence Hy)f(Hx), Hx(t), Hy(t) and Hz(t) to help us visualize the reversal mechanism?
- Hysteresis loop: why Hysteresis?
- When the reversal of magnetization is done by means of nucleation, which model should we consider for micromagnetism?v Should nucleation be considered coherent (Stoner-Wohlfarth) or incoherent (curling mode)?
- Could you please tell us the origin of non-adiabatic term in spin transfer torque? How to experimentally measure this term?
- Could double-exchange exist in systems where t2g orbitals are partially filled?
- To Prof. A. Kirilyuk: could you please give a comment for "noise" which is generated in your optical measurement system? Where is comes from? Type of noise.
- Effect of inter-particle interactions
- How does the intensity of the applied field change Tb (blocking temperature) in a FC-ZFC measurement?
- How does inter-particle interactions influence Tb (blocking) temperature?
- How does inter-particle interaction influence Hc?
- Can you please explain Barkausen volume and noise, and may be the relevant experiments?
- What is the damping factor? It has units? In which range it varies? What is its dependance (stiffness, exchange, lattice parameter)? Is it extensive or intensive property?