Analysis on the local structures for 3d¹ impurities (Ti³⁺ and V⁴⁺) in KTiPO₄

Abstract

Ti2 sites, respectively, in view of the Jahn-Teller effect. The above local orthorhombic distortion parameters in the impurity centres are found to be more significant than the host Ti1 and Ti2 sites in pure KTiOPO 4 .The sequences (C 1 > C 2 > C 3 ) of the local orthorhombic distortion parameters ρ and τ are in accordance with those of the axial and perpendicular anisotropiesΔg and δg of g factors, respectively.

Studies on the local structure and spin Hamiltonian parameters for V4+ in Na2O–PbO–Bi2O3–SiO2 glass ceramics

“…The measured impurity V 4+ center in NPBS glass ceramics with optical absorption and EPR experiments [ 16 ] originates from reduction of the doped V 5+ (in form of V 2 O 5 ) by capturing one electron. Judging from the feature of the observed g factors (i.e., g // < g ⊥ < 2, or the anisotropy g ⊥ − g // > 0 [ 16 ] ), the impurity V 4+ center in NPBS ceramics is attributed to the axially (tetragonally) compressed octahedral 3d 1 group arising from the Jahn–Teller effect through the vibration interactions, [ 20–22 ] which leads to one much shorter axial bond length R // , the other longer axial bond length R // ', and four longer planar bond lengths R ⊥ . Under the tetragonal compression distortion, the original cubic ground orbital triplet 2 T 2g for an ideal octahedral 3d 1 (V 4+ ) group may split into an orbital doublet 2 E g and an orbital singlet 2 B 2g , with the later lying lowest.…”