Giant refrigeration capacity in Gd₅B₂C₅ compounds with tetragonal structure

The search for high-performance magnetic refrigeration materials to promote the application of magnetic refrigeration technology to replace the traditional gas compression refrigeration is an urgent requirement. In this work, Gd₅B₂C₅ compound with tetragonal structure (P4/ncc; space group No. 130) was synthesized and its crystal structure, magnetism, magnetocaloric effects were systematically investigated. It undergoes a second-order magnetic phase transition from ferromagnetic to paramagnetic around approximately 132 K. The maximum magnetic entropy change and refrigeration capacity of Gd₅B₂C₅ compound are 4.5 J·kg⁻¹ K⁻¹, 219.2 J·kg⁻¹, 8.9 J·kg⁻¹ K⁻¹ and 713.8 J·kg⁻¹ under varying magnetic fields of 0–2 T and 0–5 T. It is worth mentioning that the half-peak width of the maximum magnetic entropy change is as high as 110.5 K under a varying magnetic field of 0–5 T, which will benefit the wide temperature span required for refrigeration. The present results indicate that Gd₅B₂C₅ compound is a suitable candidate for practical applications in magnetic refrigeration technology.