Rapid synthesis, structure, and magnetic properties of the non-stoichiometric oxynitride EuTaO_1.75N_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. $Pm\overline{3}m$, 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⁺.

KEYWORDS:

• Perovskite
• microstructure
• thermal analysis
• spark plasma sintering
• paramagnetic
• magnetic susceptibility

Acknowledgement

This work was supported by the National Natural Science Foundation of China (Grant No. 51702361).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51702361].