High magnetic field magnetization of quantum spin liquid candidate YbZn₂GaO₅

YbZn₂GaO₅ is a member of the Yb-based triangular lattice systems that has recently been proposed as a quantum spin liquid candidate. Previous work, including low temperature inelastic neutron scattering and specific heat measurements, suggests that YbZn₂GaO₅ can be classified as a U(1) Dirac quantum spin liquid. Here, we report on the high field magnetization of YbZn₂GaO₅ in temperatures down to 0.6 K. Between 5 K and 70 K, we find that M(H) scales according to the scaling law expected in the vicinity of a quantum critical point. This scaling results in a collapse of the data onto a single universal curve, which persists to a temperature much higher than the nearest neighbor interaction energy. Breakdown of this universal scaling below 5 K points to the emergence of a new energy scale and a non-universal regime in the YbZn₂GaO₅ phase diagram. We interpret the values of the critical exponents and compare our results to other spin liquid systems with quantum critical scaling.