Fig. 5. Magnetic and thermodynamic properties of the transition at ${\mathit{T}}_{\mathit{G}}$.

a, b In-plane and out-of-plane magnetization measurements on a single crystal. a Out-of-plane (H $\mid \mid$ c) magnetization as a function of temperature while warming up the sample after ZFC (dashed) and field cooling (solid) and measuring under a field of 10 mT. The curves are characteristic of a FM with a Curie temperature of 175 K, with a small feature at 125 K (marked with a small arrow on the ZFC curve). b In-plane (H $\mid \mid$ ab) magnetization as a function of temperature while warming up the sample after ZFC under a field of 10 mT. The curve is characteristic of an AFM with a Néel temperature of 175 K, with a feature at 125 K. Additional magnetization data can be found in Supplementary Note 3. c Single crystal heat capacity as a function of temperature for $80-200$ K. These measurements reveal no feature at 125 K.