Electron density studies on magnetic systems

In this thesis, the boundary conditions for the development of giant magnetocaloric materials are investigated. The magnetocaloric effect is found in magnetic materials, when they are subjected to an external magnetic field. This leads to abrupt magnetization changes that cause a temperature change in the material. Materials based on Fe2P show giant temperature changes around room temperature and are especially suited for cooling applications. This is due to the large magnetization change that can be realized with the application of a relatively small magnetic field around the ferro- to paramagnetic phase transition. This transition is of a first order, giving rise to latent heat and rise to
‘‘giant’’ effects. After earlier studies investigated the relation between microscopic and macroscopic properties of these materials, the focus of this thesis is on the electronic factors that play a role in the stability and phase transitions of these compounds. After all, when the mechanism behind these phase transitions is clear, is it easier to search for new materials that show similar phase transitions. Two strategies are possible: elucidating the mechanism of Fe2P-based materials or investigating materials that show similar phase transitions. The latter is described in the next paragraph...