Fig. 4: Evidence for a temperature scale T_v ≈ 60 K in SmCoIn₅.

a Magnetic susceptibility of SmCoIn₅ measured in a vibrating sample magnetometer with H = 5000 Oe, shown along with calculations of the magnetization using the crystal field model in QUANTY, and with a Curie–Weiss fit. The magnetic ordering temperature is visible at T_N = 11 K. b (inset) State populations of the three multiplet levels of SmCoIn₅, showing an inflection point in the ground state population at T = 56 K. The equivalent temperature for CeCoIn₅ is found to be T = 36 K. c Difference between the experimentally observed magnetization and calculated magnetization for different field directions. The overlayed points are the total magnetic moment of the conduction electrons at H = 6.8 T with H∥101, which we obtained from sum rule analysis of x-ray magnetic circular dichroism (XMCD) data measured at the Co L-edge assuming a Co²⁺ valence (see Supplementary Note 4 and Supplementary Figs. 5–7). d–f Temperature dependence of the a and c lattice parameters, and corresponding fits to the high temperature data with a hyperbolic form \({a}_{i}={a}_{i,0}+b\sqrt{{(T/{T}^{* })}^{2}+1}\), where b and T^* are fitted parameters with error bars smaller than the point size in the figure. The departure from the expected form occurs near T_v. g Direct current electrical resistance showing a departure from linear behavior at T_v. The solid line shows a fit to a hyperbolic form. Inset: resistance continues in a linear fashion up to T = 300 K. h Net carrier density from Hall resistance measurements with current applied along the a axis direction and field along c. Error bars represent fitted errors.