Magnetic properties and large low-field cryogenic magnetocaloric effect in the divalent europium borate Eu₂B₂O₅ compound

We herein investigated the divalent europium borate Eu₂B₂O₅ compound regarding its structural, magnetic and magnetocaloric properties by means of experimental determinations and first principal calculations. The Eu₂B₂O₅ compound was found to crystallize in a monoclinic structure (P2₁/c space group) and order ferromagnetically at ground state. A large cryogenic reversible MCE was observed in the Eu₂B₂O₅ compound around 2.7 K. The maximum values of magnetic entropy change of Eu₂B₂O₅ compound reach 13.7, 28.2 and 46.9 J/kgK under the magnetic field changes of 0–1, 0–2, and 0–5 T, respectively. The corresponding values of adiabatic temperature change and refrigerant capacity are obtained to be 3.3, 7.0, and 13.3 K and to be 37.8, 102.5, and 317.3 J/kg. These magnetocaloric parameters, especially under relatively low-field changes, are better than those of the reported candidate materials, which makes the Eu₂B₂O₅ compound attractive for cryogenic MR applications.