In a significant stride towards enhancing energy-efficient refrigeration technologies, researchers have employed a novel approach to study the magnetocaloric effect, a phenomenon crucial for magnetic refrigeration. The study, led by Jorge Revuelta-Losada from the Multidisciplinary Unit for Energy Science at the University of Seville, Spain, utilized lock-in infrared thermography (LIT) to gain unprecedented insights into the behavior of magnetocaloric materials under dynamic conditions.
The research, published in the journal ‘Materials & Design’ (translated as ‘Materials & Design’), focused on four paradigmatic magnetocaloric materials, each exhibiting different types of thermomagnetic phase transitions. These materials included gadolinium (Gd), a LaFeMnSi compound, and two Heusler alloys, NiMnIn and NiCoMnTi. The team subjected these materials to an oscillating magnetic field and measured the reversible adiabatic temperature change (ΔTadrev) with remarkable precision.
Revuelta-Losada explained, “Lock-in thermography increases the resolution of ΔTadrev measurements by two orders of magnitude compared to traditional thermography. This allows us to detect features in the material’s response that would otherwise be challenging to identify.”
The study revealed that while the ΔTadrev measurements remained reversible against field oscillations, first-order thermomagnetic phase transitions driven by non-saturating fields exhibited different behaviors for heating and cooling curves. This phenomenon, known as thermal hysteresis, underscores the importance of direct characterization methods for the magnetocaloric response.
“The phase Φ with respect to the excitation serves as an indicator of the phase transition dynamics,” Revuelta-Losada added. “This highlights the significance of direct characterization methods over indirect approaches in the design of materials for efficient refrigeration devices.”
The implications of this research are substantial for the energy sector. Magnetic refrigeration, which relies on the magnetocaloric effect, promises to be more energy-efficient and environmentally friendly compared to conventional vapor-compression refrigeration. By understanding the dynamic behavior of magnetocaloric materials, researchers can develop more effective and efficient refrigeration technologies.
This study not only advances our fundamental understanding of magnetocaloric materials but also paves the way for practical applications. As the world seeks sustainable and energy-efficient solutions, the insights gained from this research could shape the future of refrigeration and cooling technologies, potentially revolutionizing the energy sector.