Rapid synthesis,structure,and magnetic properties of the non-stoichiometric oxynitride EuTaO 1.75 N 1.25

Abstract

Non-stoichiometric oxynitride with a composition of EuTaO_1.75N_1.25 was synthesized in <10 min through urea route combined with modified pressureless spark plasma sintering apparatus. The electronic properties of EuTaO_1.75N_1.25 was investigated by first-principles calculations. X-ray powder diffraction revealed that EuTaO_1.75N_1.25 crystallized with the cubic perovskite-type structure, S.G. , and a lattice constant of a = 4.0283(7) Å. Thermogravimetric studies revealed that EuTaO_1.75 N_1.25 decomposed at around 345 under the oxygen atmosphere, giving a final product of decomposition as EuTaO₄ and Eu₅Ta₄O₁₅ oxides. Magnetic susceptibility measurements indicated EuTaO_1.75 N_1.25‘s paramagnetic behavior with an estimated T _c =9.9 K. The saturation moment of 6.82 μB which is smaller than 7 μ_B expected for Eu²⁺ can be due to the existence of Eu³⁺. The extremely low value obtained for remanence and coercive field agrees to the isotropic character of the ⁸S7/2 ground state associated to the Eu²⁺.