Site-Selective d¹⁰/d⁰ Substitution in an S = ¹/₂ Spin Ladder Ba₂CuTe_1–xW_xO₆ (0 ≤ x ≤ 0.3)

Abstract

This is a repository copy of Site-selective d10/d0 substitution in a S=1/2 spin ladder Ba2CuTe1−xWxO6 (0≤x≤0.3).

Partitioning the Two-Leg Spin Ladder in Ba2Cu1 – xZnxTeO6: From Magnetic Order through Spin-Freezing to Paramagnetism

“…The zero-field heat capacity (C P /T vs T) data of the x = 0, 0.1, 0.2, and 0.3 samples is plotted in Figure 9a. As in previous reports, no clear Neèl transition can be observed for Ba 2 CuTeO 6 at ∼14 K. 10,18 The close proximity to the QCP creates quantum fluctuations that smear out the lambda (λ) ordering peak. The C P /T vs T curve of x = 0.1 is similar, with no evidence of a λ-peak about the T N = 8 K indicated by the dotted line in the C P /T vs T 2 plot in Figure 9b.…”

“…The γ-contribution was almost zero for x = 0 (γ = 1.4(1) mJ mol −1 K −2 ), in agreement with previous reports, where γ = 3.5(4) mJ mol −1 K −2 . 18 The value of γ was also close to zero for x = 0.1 (γ = 8.6(1) mJ mol −1 K −2 ). The low-temperature C P /T vs T 2 data for x = 0.2 and x = 0.3 could not be fitted using eq 7.…”

“…Table 2 shows that the μ eff is close to the previously reported value for Ba 2 CuTeO 6 and Ba 2 CuTe 1 − x W x O 6 . 10,18 The χ vs T data for 0 ≤ x ≤ 0.3 were modeled using the isolated two-leg spin ladder model between 35 and 300 K. The model is based on Quantum Monte Carlo (QMC) simulations of isolated two-leg spin ladders and has been employed to model Ba 2 CuTeO 6 and Ba 2 CuTe 1 − x W x O 6 previously. 10,18,22 The fitting parameters, J leg , J rung /J leg , and Landèg-factor, for x = 0 were near identical to previous reports: J leg = 89.2(3) K, J rung / J leg = 0.972 (6), and g = 2.231(2).…”

“…10,18 The χ vs T data for 0 ≤ x ≤ 0.3 were modeled using the isolated two-leg spin ladder model between 35 and 300 K. The model is based on Quantum Monte Carlo (QMC) simulations of isolated two-leg spin ladders and has been employed to model Ba 2 CuTeO 6 and Ba 2 CuTe 1 − x W x O 6 previously. 10,18,22 The fitting parameters, J leg , J rung /J leg , and Landèg-factor, for x = 0 were near identical to previous reports: J leg = 89.2(3) K, J rung / J leg = 0.972 (6), and g = 2.231(2). 10,18 The x = 0.1 data could be described using the spin ladder model but, as shown in Figure 4, began to fail for x = 0.2 as the T max feature is suppressed.…”

“…14−17 We have recently demonstrated that the intra-ladder interactions in Ba 2 CuTeO 6 can be site-selectively tuned through W 6+ substitution. 18 W 6+ is almost exclusively substituted for Te 6+ at the corner-sharing site (B″(c)) rather than the face-sharing trimer site (B″(f)) indicated in Figure 1. Through the d 10 /d 0 effect, the competing d 10 Te 6+ and d 0 W 6+ interactions strongly suppress the J rung , while the J leg is slightly strengthened.…”