Magnetic anisotropy and magnon gap state of SmB4 single crystal

Abstract

This paper investigates the magnetic and electronic properties of a single-crystal SmB4. Two magnetic phase transition temperatures at TN=25 K and Tm≈7 K were revealed by the temperature-dependent magnetization for an applied magnetic field perpendicular to the c-axis. Magnetic transition at TN=25 K is caused by the antiferromagnetic order with Sm3+ moments that lie on the ab-plain. However, the antiferromagnetic transition temperature was not observed in a temperature-dependent magnetization for an applied magnetic field along the c-axis. The second transition occurring at Tm≈7 K was observed for directions both parallel and perpendicular to the c-axis and was suppressed by applying magnetic fields. Interestingly, the second transition exhibited local maximum behavior, implying the second order phase transition. Furthermore, temperature-dependant resistivity showed a magnon gap feature below the second magnetic transition temperature T<Tm(=7 K).