Structure and Magnetocaloric Properties of Two Cadmium Gadolinium Borates

Two cadmium–gadolinium-borates, CdGdB₅O₁₀ and Cd₄GdB₃O₁₀, were synthesized as polycrystalline samples, and their single crystals were also grown. Monoclinic structures in space groups P2₁/n and Cm were identified for the two compounds, with magnetic properties characterized through M–T and M–H measurements. The maximum magnetic entropy change (−ΔS_M^max) of CdGdB₅O₁₀ reaches 23.94 J·kg^–1·K^–1 at 5 T and 3 K, approaching the value reported for commercial Gd₃Ga₅O₁₂ under identical conditions. Cd₄GdB₃O₁₀ exhibits a −ΔS_M^max of 13.96 J·kg^–1·K^–1 at 5 T and 2 K, comparable to Dy₃Ga₅O₁₂. These two cadmium–gadolinium-borates may have potential for cryogenic magnetic cooling applications due to their high −ΔS_M^max, broad entropy plateau, and stable structure. Additionally, the optical and thermal properties of CdGdB₅O₁₀ were investigated.