Fig. 4

Comparison of the MCE results with the susceptibility data. a Contour plot of the magnetic susceptibility multiplied by the power of temperature, χT^0.83, in the T–H plane, determined by us in ref. ¹⁶. The yellow and dark-red areas represent the quantum critical (QC) and QSL states, respectively, which are separated by the crossover region (light-red area). The onset field of the τ increase, H*, shown by the circles, falls on the contour line (dashed line), χT^0.83 = 2.3 mJ K^0.83 T⁻² mol⁻¹. The blue solid line indicates a linear fit of H*. b The zero-temperature extrapolation of the (τT^1.3)⁻¹ values raised to the power p, \((\tau T^{1.3})_0^{ - p}\), and the Pauli-like susceptibility, χ_P, as a function of magnetic field. χ_P is determined based on the susceptibility data in ref. ¹⁶. The solid line represents a power-law fit of χ_P with the exponent −0.73