Magnetic materials: Turning up the heat on disordered magnets

Dr. Fritz Körmann, researcher at the department of Materials Science and Engineering, and a research team with researchers from Japan and Germany,  have developed a numerical method to predict the atomic vibrations of disordered magnetic solids above zero temperature by turning up the heat on disordered magnets. Their research results were published in npj Computational Materials this month of which Fritz Körmann is the second author.

Accurate methods for computing the vibrational modes of materials at different temperatures are needed to determine thermodynamic properties from first principles. However, for magnetic alloys the effects of the non-uniform distribution of atoms and quantum magnetic behaviour each require special techniques for calculations to be tractable.

The researchers have designed a scheme that combines an approach for ordered magnetic systems with established approximations for disordered materials. Their method successfully captures the unusual thermal expansion properties of Invar alloys, which are strongly affected by the interplay of atomic and magnetic fluctuations, and should provide insights into the physics of other complex materials such as high entropy alloys.

Click here for the publication