Thermal annealing effects in polycrystalline EuTiO3 and Eu2Ti2O7

Abstract

Using time-differential perturbed angular correlation of γ rays, we investigated the electric-field gradient of polycrystalline EuTiO3 and Eu2Ti2O7, with 181Hf(181Ta) as a probe, following different thermal treatments. The measurements were performed at ISOLDE-CERN following 80 keV implantation at the Bonn Radioisotope Separator. The experimental results indicated successful induction of different phases in the implantation recovery process at 1273 and 1373 K. These observations were combined with ab initio calculations and X-ray diffraction measurements. A comparison of ab initio calculated electric-field gradients with the measured values discriminates between different structures and defects and rules out many possible cases. The Ta probe at the Ti site in the Eu2Ti2O7 phase is found to be the most probable case of site occupation after annealing at 1373 K, while annealing at 1273 K keeps EuTiO3 in the vicinity of the Ta probe. A discussion of the hyperfine interactions that promote variation in the interaction strength at the 181Ta site is presented.

Crystallization kinetics and structural properties of nanocrystalline europium-yttrium-titanate (Eu0.5Y0.5)2Ti2O7

“…provided in Supplementary Table 1. (10), Y = 0.50 (9), Ti = 0.00(5), B: Eu = 0.00 (10), Y = 0.00 (9), and Ti = 1.00 (5) for general formula A2B2O7.…”

“…Refinement also confirmed that the phase was perfectly ordered. The refined occupancies were Eu = 0.50 (10), Y = 0.50 (9), and Ti = 0.00(5) in site A, and Eu = 0.00 (10), Y = 0.00 (9) and Ti = 1.00 (5) in site B for the general pyrochlore formula A2B2O7.…”

“…Therefore, the synthesis and thermal processing must be precisely tailored to maximize the regularity of the crystal structure. The non-uniform distribution of RE ions, increased defects, and lattice frustration can significantly modify the final material properties [9,10]. Inappropriate heat treatment can result in an undesirable transformation of the pyrochlore structure, such as that of perovskite [11].…”

Investigation of the Structural, Electrical and Magnetic Properties of Vanadium Substituted Mn-Zn Ferrites

“…By modifying the type and quantity of defects, a relatively tiny amount of dopant may significantly change the characteristics of Mn-Zn ferrites. The dynamics of grain boundary motion, phase transition temperature, pore clearance, and pore mobility are all impacted by defects [10]. In Mn-Zn ferrites of different stoichiometry, like Mn0.58Zn0.37Fe2.05-xGdxO4, Mn0.5Zn0.5ScyFe2-yO4, and Mn0.3Zn0.7Fe2-xDyxO4, the rare-earth metal substitution results in the 4f-3d coupling, which might enhance magnetic and electrical properties [3,11,12].…”