Site-Selective d 10 /d 0 Substitution in an S = 1 / 2 Spin Ladder Ba 2 CuTe 1- x W x O 6 (0 ≤ x ≤ 0.3).

Isovalent nonmagnetic d 10 and d 0 B″ cations have proven to be a powerful tool for tuning the magnetic interactions between magnetic B' cations in A 2 B'B″O 6 double perovskites. Tuning is facilitated by the changes in orbital hybridization that favor different superexchange pathways. This can produce alternative magnetic structures when B″ is d 10 or d 0 . Furthermore, the competition generated by introducing mixtures of d 10 and d 0 cations can drive the material into the realms of exotic quantum magnetism. Here, Te 6+ d 10 was substituted by W 6+ d 0 in the hexagonal perovskite Ba 2 CuTeO 6 , which possesses a spin ladder geometry of Cu 2+ cations, creating a Ba 2 CuTe 1- x W x O 6 solid solution ( x = 0-0.3). We find W 6+ is almost exclusively substituted for Te 6+ on the corner-sharing site within the spin ladder, in preference to the face-sharing site between ladders. The site-selective doping directly tunes the intraladder, J rung and J leg , interactions. Modeling the magnetic susceptibility data shows the d 0 orbitals modify the relative intraladder interaction strength ( J rung / J leg ) so the system changes from a spin ladder to isolated spin chains as W 6+ increases. This further demonstrates the utility of d 10 and d 0 dopants as a tool for tuning magnetic interactions in a wide range of perovskites and perovskite-derived structures.