Thermodynamic and transport properties of high-quality single crystals of the altermagnet CrSb

Abstract: Altermagnetism (AM) is an emerging magnetic order unifying essential characteristics of ferromagnetic and antiferromagnetic states. Despite zero net magnetization, altermagnets (AMs) exhibit spin-split electronic bands and lifted altermagnon spin degeneracy. The altermagnet CrSb has attracted significant interest owing to its large spin-splitting energy. In this paper, we present the growth details of high-quality single crystals of CrSb using the self-flux method. We obtained large (001) oriented hexagonal crystals, up to 2 $\times$ 2.5 $\times$ 1 mm$^3$ in size. We investigated physical properties of the CrSb single crystals through measurements of electrical resistivity, magnetic susceptibility, and specific heat. The residual resistivity ratio (RRR) around 11 indicating the higher crystal quality than previous reports. A pronounced positive magnetoresistance of up to 80\% is observed at 3.5 K. The specific heat was measured down to 0.45 K, revealing the Sommerfield coefficient $γ$ = 4.0 $\pm$ 0.08 mJ mol$^{-1}$ K$^{-2}$, indicating weak electronic correlation among the conduction electrons. The room temperature specific heat exceeds the Dulong-Petit limit due to a broad magnon contribution from the altermagnetic order. The data yield the Debye temperature of 321 $\pm$ 5 K and magnon energy gap $\sim$ 16 $\pm$ 1 meV. We also reveal that stoichiometric CrSb does not exhibit superconductivity down to 0.1 K. These findings underscore CrSb as a viable altermagnet for room temperature magnonic and spintronic applications.