Isostructural Sr2CuBO6, B=W or Te, exhibit different magnetic structures k=[0 1/2 1/2] vs [1/2 1/2 0], leading to the suggestion of a reversal in the ratios of the nearest and next nearest neighbour interactions, which is proposed to be due to the difference in the superexchange interactions mediated via the hexavalent B ion. Using INS we have identified that J2>>J1 for B=W, and now we wish to investigate the proposal that J1>J2 for B=Te, before looking at the solid solutions between W and Te to explore the critical regime for J2/J1=1/2, which may host a quantum spin liquid.

2019