electro-caloric; magneto-caloric; multiferroics; solid state refrigeration; atomistic simulations
Edström Alexander, Ederer Claude (2018), First-principles-based strain and temperature-dependent ferroic phase diagram of SrMnO3, in Physical Review Materials
, 2(10), 104409-104409.
Grünebohm Anna, Ma Yang-Bin, Marathe Madhura, Xu Bai-Xiang, Albe Karsten, Kalcher Constanze, Meyer Kai-Christian, Shvartsman Vladimir V., Lupascu Doru C., Ederer Claude (2018), Origins of the Inverse Electrocaloric Effect, in Energy Technology
, 6(8), 1491-1511.
Marathe Madhura, Ederer Claude, Grünebohm Anna (2018), The Impact of Hysteresis on the Electrocaloric Effect at First-Order Phase Transitions, in physica status solidi (b)
, 255(2), 1700308-1700308.
Marathe Madhura, Renggli Damian, Sanlialp Mehmet, Karabasov Maksim O., Shvartsman Vladimir V., Lupascu Doru C., Grünebohm Anna, Ederer Claude (2017), Electrocaloric effect in BaTiO3 at all three ferroelectric transitions: Anisotropy and inverse caloric effects, in Physical Review B
, 96(1), 014102-014102.
The application/removal of an external electric or magnetic field to a material containing either electric or magnetic dipole moments decreases/increases the degree of orientational disorder (i.e. entropy) in the system. If the corresponding material is thermally isolated from the environment this leads to a change in temperature --- the so-called "electro-caloric" or "magneto-caloric" effects. It has been shown that temperature changes of several Kelvin can be achieved for example in thin films close to a first order ferroelectric phase transition. This observations has generated a lotof interest in using the electro-caloric effect for cooling applications. Solid state refrigerators have enormous potential for reducing electricity consumption, and thus the worldwide emission of greenhouse gases. Furthermore, the scalable mechanism opens up further applications such as cooling of microsystems based on thin films. However, in order to achieve this goal, optimized materials with large electro-caloric response within a suitable temperature interval have to be identified.In this project, we are using first principles-based simulations to identify the factors promoting large caloric response in thin film materials, and in particular to explore novel ways to enhance caloric response by utilizing cross-coupling between dielectric and magnetic degrees of freedom, i.e. by exploiting so-called "multi-caloric" effects. The use of multiferroic materials offers great potential for enhanced temperature- and entropy-changes, if the magnetic and ferroelectric degrees of freedom order simultaneously. In addition, multiferroic coupling and strain-tuning can be used to trigger the giant caloric response of certain magnetic materials via an applied electric field. Our simulations will clarify the underlying physical mechanisms and provide guidelines for future optimization of caloric effects.