MULTICALORICS · Multicaloric refrigeration enhanced by multisite interactions: Bridging theory and experiment

Multicaloric refrigeration enhanced by multisite interactions: Bridging theory and experiment

Magnetic materials play a fundamental role in many modern solid-state technologies greatly impacting our society. These technologies include critical devices for mobility, ground transportation, energy generation, as well as spintronic devices, such as neuromorphic computing inspired by the human brain and innovative non-volatile memories. An important emerging application is the so-called caloric refrigeration based on magnetic materials. This is a novel cooling technology aimed to replace the harmful greenhouse gases currently prevalent in our society with environmentally friendly solid-state refrigerants to urgently combat the climate change. Our action has focused on a collaborative effort, combining theoretical research conducted by the lead researcher, with experimental work at the host institution, the University of Barcelona, with the overall objective to uncover and understand new and more efficient refrigerant magnetic materials. Cooling with magnetic materials is typically achieved by applying magnetic fields or mechanical stresses to them. However, caloric refrigeration has yet to become commercially viable due to the reliance on costly neodymium-based permanent magnets needed to generate sufficiently strong magnetic fields, and the fact that some materials show operational lifespan reduced by mechanical fatigue. Our research addresses these challenges by exploring a novel approach: the simultaneous application of magnetic and mechanical stimuli to minimize the required work and maximize the cooling effect, known as the multicaloric effect. Our theoretical work is grounded in first-principles (ab initio) calculations, which rely exclusively on fundamental laws and, therefore, are instrumental in guiding and supporting the experimental discovery of new multicaloric materials. A key focus of our research has been the development of a novel computational approach that accurately accounts for the coupling between the material’s magnetism with its elasticity and the vibrations of its constituent atoms at finite temperatures—factors that are crucial to the underlying mechanisms of caloric refrigeration. This advanced computational tool is designed to predict materials with cooling power enhanced by multisite interactions, a newly identified mechanism based on complex interactions between atomic-scale magnetic degrees of freedom. We aim to deepen our understanding on the origin of multisite interactions and on how to nanostructure magnetic materials with cooling power boosted by them.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз