Substitutional site of Mn⁴⁺ ion and local compressibility of this Mn⁴⁺ center in Mn⁴⁺-doped Sr₄Al₁₄ O₂₅ crystal

ABSTRACT

The local compressibility of (MnO₆)⁸⁻ octahedral cluster for Mn⁴⁺ ion in the octahedral Al³⁺ site of Sr₄Al₁₄O₂₅:Mn⁴⁺ crystal is investigated by analyzing the dominant pressure dependence of R-line position (i.e. ²E→⁴A₂ transition). The obtained local compressibility is much greater than that in Al₂O₃: Mn⁴⁺ crystal, suggesting that the average Al³⁺–O²⁻ distance $\overline{R}$ of the replaced (AlO₆)⁹⁻ octahedron in Sr₄Al₁₄O₂₅ is much greater than that in Al₂O₃. By comparing the average Al³⁺–O²⁻ distances $\overline{R}$ in the three octahedral Al³⁺ sites, Al4, Al5 and Al6, in Sr₄Al₁₄O₂₅ crystal, we propose that the dominant substitutional site of Mn⁴⁺ ion is Al4 site which has the largest average Al³⁺–O²⁻ distance. The results are discussed.

KEYWORDS:

• Substitutional site
• local compressibility
• optical spectrum
• Mn⁴⁺
• Sr₄Al₁₄O₂₅

Disclosure statement

No potential conflict of interest was reported by the authors.