The effect of high pressure on the electric field gradients at two inequivalent lattice sites of tantalum in ω-zirconium

Abstract

The pressure variation of the electric field gradients at substitutional tantalum atoms on the two lattice sites (A and B) of ω-zirconium have been determined to be (∂ lnq ^A/∂P)_T = −1.05(26)10⁻³ kbar⁻¹ and (∂ lnq ^B/∂P)_T = +6.03(40)10⁻³ kbar⁻¹. In addition the thermal expansion coefficients of the unit cell of ω-Zr were found to be α_‖ = +3.5(3)10⁻⁶ K⁻⁶ and α_⊥ = +7.9(4)10⁻⁶ K⁻¹. A combined analysis of the pressure dependence and the previously determined temperature dependence of the electric field gradients supports the assumption of two different bonding types at the A and B sites.