Fig. 4: Comparison of magnetization data of A₃ReO₅X₂ (A = Ca, Sr, Pb) with theoretical calculations based on the OFTLM.

Panels a–e show the temperature dependence of the magnetic susceptibility measured at 7 T^52,53, where a T-independent component χ₀ is subtracted. Panels f–j show quasi-isentropic magnetization curves in the field-increasing (solid lines) and field-decreasing (dashed lines) processes measured at the initial temperature of T_ini = 5 K using a single-turn coil megagauss generator. The field derivative of the magnetization dM/d(μ₀H) in the field-decreasing process is displayed in the right axis. Experimental curves are shown by colored lines, and theoretical curves fitted to each experimental data are shown by black lines. Theoretical M–H curves represent isentropic curves for T_ini = 5 K. The fitting parameters for each compound are summarized in Table 2.