Abstract
The magnetic ground state of the pyrochlore Yb2GaSbO7 has remained an enigma for nearly a decade. The persistent spin fluctuations observed by muon spin relaxation measurements at low temperatures have not been adequately explained for this material using existing theories for quantum magnetism. Here we report on the synthesis and characterisation of Yb2GaSbO7 to elucidate the central physics at play. Through DC and AC magnetic susceptibility, heat capacity, and neutron scattering experiments, we observe evidence for a dynamical ground state that makes Yb2GaSbO7 a promising candidate for disorder-induced spin-liquid or spin-singlet behaviour. This state is quite fragile, being tuned to a splayed ferromagnet in a modest magnetic field μ0Hc∼1.5T<math><mrow><msub><mi>μ</mi><mn>0</mn></msub><msub><mi>H</mi><mi>c</mi></msub><mo>∼</mo><mn>1.5</mn><mspace></mspace><mi>T</mi></mrow></math>.