Ba5Gd3(BO3)6F: A new alkaline earth-rare earth fluoroborate with magnetocaloric effect.

A new alkaline-earth and Gd3+ borate, Ba 5 Gd 3 (BO 3) 6 F, has been successfully grown through a high-temperature solution method employing a BaF 2 -NaF-B 2 O 3 flux. This compound crystallizes in the monoclinic space group P 2 1 / c with lattice parameters of a = 13.679(4) Å, b = 8.694(3) Å, c = 7.664(2) Å, β = 99.116(7)°, V = 899.9(5) Å3, and Z = 1. Its three-dimensional structure consists of the [Ba/GdO] polyhedra and [FBa 4 Gd 2 ] octahedra layers. Magnetic analysis reveals that Ba 5 Gd 3 (BO 3) 6 F exhibits a magnetocaloric effect with a maximum −ΔS m of 29.86 J kg–1 K–1 at 3 K and 9 T. Additionally, the thermal stability, along with infrared (IR) and ultraviolet–visible–near-infrared (UV–Vis–NIR) diffuse reflectance spectra, were thoroughly examined. First-principles calculations further explored the electronic band structure and densities of states. A new Ba 5 Gd 3 (BO 3) 6 F single crystal has been obtained using a high-temperature solution method with BaF 2 -NaF-B 2 O 3 system as flux. Ba 5 Gd 3 (BO 3) 6 F exhibits paramagnetism and demonstrates a magnetocaloric effect with a –ΔS m value of 29.86 J kg−1 K−1 at 3 K and 9 T, approaching its paramagnetic limit. [Display omitted] • A new borate, Ba 5 Gd 3 (BO 3) 6 F, was obtained. • The magnetocaloric properties of Ba 5 Gd 3 (BO 3) 6 F were investigated. • Ba 5 Gd 3 (BO 3) 6 F exhibits a maximum −ΔS m reaching 88.11 % of the theoretical value. • Ba 5 Gd 3 (BO 3) 6 F has high stability. [ABSTRACT FROM AUTHOR]