Can erbium dopant occupy both cation sites in cubic barium titanate via a mechanism different than self‐compensation?

Abstract

The defect energetics for several dopant incorporation modes and the dielectric–electric properties in Er‐doped BaTiO3 were studied by numerical simulations and the dielectric modulus formalism. Two “mixed” incorporation modes, both compatible with the existence of oxygen vacancies, are proposed. Simulation results for the solution energies show that, despite self‐compensation is the most favourable mode, the mixed modes exhibit quite similar energies and, therefore, could be active under some conditions. The incorporation of Er3+ into the BaTiO3 lattice decreases the dc conductivities with respect to the undoped case at high temperatures. Molecular Dynamics calculations and experimental measurements about conducting properties of Er‐doped BaTiO3 allow one to calculate activation energies for ionic conductivity, which agree with data for oxygen migration. Experimental and Molecular Dynamics data are then correlated with the possible defect configurations. Scheme of the defect clusters corresponding to the proposed mixed incorporation mechanisms: (a) “Ti‐vac” and (b) “Ba‐vac”. Green, grey, blue, and red balls correspond, respectively, to Ba2+, Ti4+, Er3+, and O2− ions.

Incorporation of Zn2+ ions into BaTiO3:Er3+/Yb3+ nanophosphor: an effective way to enhance upconversion, defect luminescence and temperature sensing

“…So, in a word, Zn-addition improves the microstructure and dielectric properties of barium titanate. This work concludes that doping of Zn 2+ with Er 3+ /Yb 3+ ions is a promising 30 route to enhance the multi-functionality of BaTiO 3 . Therefore, accurate sensing and mapping of temperature in a non-invasive way is a challenging field of research.…”

“…By plotting [F(R ∞ )hν] 1/m against hν, the best straight line fitting was obtained for m= ½ (direct type bandgap). This substitution leads to change in the compositional 30 and structural properties, because of difference in charge, difference in radii and modification of Ti-O bond length by Zn-O bond length. 6 formed.…”

“…The values of 'n' for two pump power regions are presented in Table 2. 7c)-(a) ETU-1: 2 F 5/2 (Yb 3+ ) + 4 I 15/2 (Er 3+ ) → 2 F 7/2 (Yb 3+ ) + 4 I 11/2 (Er 3+ ) (b) ETU-2: 2 F 5/2 (Yb 3+ ) + 4 I 11/2 (Er 3+ ) → 2 F 7/2 (Yb 3+ ) + 4 F 7/2 (Er 3+ ) (c) ETU-3: 2 F 5/2 (Yb 3+ ) + 4 I 13/2 (Er 3+ ) → 2 F 7/2 (Yb 3+ ) + 4 F 9/2 (Er 3+ ) 30 The Er 3+ ions raised to the 4 F 7/2 level by ETU-2, relaxes nonradiatively to 2 H 11/2 / 4 S 3/2 levels and subsequently, radiative transition to ground state ( 4 I 15/2 ) yields 525 nm/550 nm emission bands. 7c), all three transitions should be through two photon absorption process (n ~ 2.0).…”

“…to biomedical and therapeutic applications [1][2][3][4][5][6]. 30 Furthermore, the public need of cheap and reliable multitasking materials also motivated researchers to think on multifunctional and hybrid materials. 30 Furthermore, the public need of cheap and reliable multitasking materials also motivated researchers to think on multifunctional and hybrid materials.…”

First-principles study of neutral defects in Fe-doped cubic barium titanate

“…Note that mode 3 is not the only one able to justify the presence of oxygen vacancies in this system, but just the simplest one. Actually, some other modes have been proposed in the literature [59].…”