Anomalous Behavior of Low Temperature Specific Heat in HgCr2Se4

Low temperature specific heat (C (p) ) characterization on high-quality HgCr2Se4 single crystal was performed between 0.5 K and 10 K. The result provides conceivable evidence for the existence of competing ferromagnetic (FM) and antiferromagnetic (AFM) interactions in narrow temperature and temperature windows. The result suggests that magnetic interactions competition, as well as the Schottky anomaly, neglected previously in HgCr2Se4 due to the fragile AFM interaction and spin-lattice coupling, also play key roles in giving rise to the exotic magnetic behaviors.