Magnetic phase transition and magnetic properties in rare-earth-based RAl3C3 layered carbides

High-purity RAl₃C₃ phases (R = Nd, Gd, Tb, Dy, Ho, Er and Tm) have been synthesized and all crystallized in hexagonal structure with the space group (#194) P6₃/mmc. Lattice parameters are decreased from R = Nd to R = Tm due to lanthanide contraction. Two nonlinear antiferromagnetic states are found in NdAl₃C₃ phase. While simple ferromagnetic state is observed for R = Gd, Tb, Ho and Er cases. A high coercivity of 0.45 T has been achieved in TbAl₃C₃ phase at 4 K indicating the uniaxial magnetocrystalline anisotropy. Before entering into paramagnetic state, DyAl₃C₃ phase undergoes the complex magnetic phase transition with increasing temperature. All these phase transitions are of second-order due to nonhysteresis.