Unusual antiferromagnetic properties affected by antiferroquadrupolar interaction in TbB2C2

Abstract Neutron scattering experiments were carried out on TbB2C2 with T N =21.7 K under high energy resolution in order to investigate the diffuse scattering and the incommensurate structure in the antiferromagnetic state. At 3.9 K , the energy width of both the satellite peak and the diffuse scattering corresponding to the energy resolution of 0.2 meV . With increasing temperature, only the satellite peak was disappeared far below TN around 13 K where no anomaly was observed in the specific heat and the magnetic susceptibility. Since the disappearance temperature of the satellites depends on the energy resolution of spectrometer, the dynamical component would affect the incommensurate structure in TbB2C2.