Possible quantum spin liquid state in disorder-induced spin-1/2 frustrated 3D pseudocubic Ba3CuTa2O9

A polycrystalline sample (about 2 gram) of the title compound Ba3CuTa2O9 was prepared by the conventional solid-state reaction method. Rietveld refinement of the XRD data at T = 300 K confirms that the material is in a single phase with P4/mmm (No. 123) space group. Curie-Weiss fitting of magnetic susceptibility data indicates strong antiferromagnetic coupling (AFM CW temperature - 24 K) among the Cu2+ (S = 1/2) moments arranged in a 3D pseudocubic framework. Our susceptibility (down to 1.8 K) and specific heat (down to 690 mK) depict no evidence of long-range magnetic ordering. These measurements indicate that Ba3CuTa2O9 might host a quantum spin-liquid (QSL) state. Further, the data collapsing behavior of field-dependent magnetization at several temperatures and temperature-dependent susceptibility at several fields with appropriate scaling exponents suggests the possible existence of a random spin-singlet (RSS) state on top of a QSL state. Thus, it is essential to perform the muSR experiments to explore the putative QSL behavior in the well-characterized polycrystalline sample of Ba3CuTa2O9.