Mastering the theory of coupled spin-lattice phenomena for design of new magnetocaloric alloys

In this theoretical materials science project I probe a new path for finding novel and improved alloys for magnetic cooling by the magnetochaloric effect (MCE).

The basic idea is that the spin-lattice coupling, originating on the atomic and electronic scale, is critical for a material to display a gigantic MCE.

The reason is that this coupling is needed in order for a material to contribute with vibrational entropy to the entropy difference upon a magnetic field induced phase change.This idea is tested using theoretical tools, just recently developed in my own research group, able to simulate coupled spin-lattice dynamics from first principles.

These simulations are used to derive total entropy change and adiabatic temperature change and compare them to separate spin and lattice contributions.

Furthermore a specific focus is given to the effect of the atomic configurational disorder in the considered alloys, in terms of the effect it has on both spin-lattice coupling and MCE.The well known magnetocaloric materials like Gd, FeRh, La(Fe,Si)13, and Heusler alloys will be investigated for benchmarking.

To find new candidate materials, high-throughput calculations searching for strong spin-lattice coupling will be performed.

Promising materials will be studied in detailed calculations and communicated to a expert network of experimental collaborators.