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

Remarkably, doping isovalent d10 and d0 cations onto the B'' site in A2B'B''O6 double perovskites has the power to direct the magnetic interactions between magnetic B' cations. This is due to changes in orbital hybridization, which favors different superexchange pathways, and leads to the formation of alternative magnetic structures depending on whether B'' is d10 or d0. Furthermore, the competition generated by introducing mixtures of d10 and d0 cations can drive the material into the realms of exotic quantum magnetism. Here, a W6+ d0 dopant was introduced to a d10 hexagonal perovskite Ba2CuTeO6, which possesses a spin ladder geometry of Cu2+ cations, creating a Ba2CuTe1−xWxO6 solid solution (x = 0 - 0.3). Neutron and synchrotron X-ray diffraction show that W6+ is almost exclusively substituted for Te6+ on the corner-sharing site within the spin ladder, in preference to the face-sharing site between ladders. This means the intra-ladder interactions are selectively tuned by the d0 cations. Bulk magnetic measurements suggest this suppresses magnetic ordering in a similar manner to that observed for the spin-liquid like material Sr2CuTe1−xWxO6. This further demonstrates the utility of d10 and d0 dopants as a tool for tuning magnetic ground states in a wide range of perovskites and perovskite-derived structures.