In the realm of energy-efficient cooling technologies, a team of researchers from the Indian Institute of Technology Hyderabad, led by Ravi Kiran Dokala, Shaona Das, and Subhash Thota, has made a significant stride. Their work focuses on the magnetic and phonon properties of a compound that could potentially revolutionize magnetic refrigeration, a field that promises to be more energy-efficient and environmentally friendly than conventional vapor-compression cooling methods.
The researchers investigated the effects of substituting cerium (Ce) for gadolinium (Gd) in the compound GdCrO3, an orthorhombic perovskite. They found that the substituted compound, Gd0.9Ce0.1CrO3 (GCCO), exhibits a remarkably large magnetic entropy change. This change is among the highest reported for rare-earth orthochromites, reaching approximately 45-40 J/kg-K for a magnetic field change of 90-70 kOe at 3 K. This substantial change in magnetic entropy is a key factor in the efficiency of magnetic refrigeration systems.
The study also revealed that the incorporation of Ce3+ ions drives a modification in the spin-flip transition of the compound, leading to a reorientation of the spin axis. This reorientation is governed by Zeeman energy and produces pronounced field-induced irreversibility between different magnetization processes. The interplay of spin-only magnetocrystalline anisotropy from Cr3+ ions and spin-orbit-driven magnetic moments of Gd3+ and Ce3+ ions results in pronounced spin-phonon coupling. This coupling is manifested through the A1g(6) vibrational mode and is consistent with behavior reported in isostructural magnetic perovskites.
The practical applications of this research for the energy sector are significant. Magnetic refrigeration, which relies on the magnetocaloric effect—the change in temperature of a magnetic material when subjected to a changing magnetic field—could benefit greatly from the enhanced magnetic entropy change observed in GCCO. This could lead to more efficient and environmentally friendly cooling technologies, reducing the energy consumption and greenhouse gas emissions associated with conventional cooling methods.
The research was published in the journal Physical Review B, a reputable source for cutting-edge research in condensed matter physics. The findings of this study not only advance our understanding of the magnetic and phonon properties of orthochromites but also pave the way for innovative applications in the energy sector, particularly in the field of magnetic refrigeration.
This article is based on research available at arXiv.