Magnetic and fermi surface properties in ferromagnets NdRh3B2 and GdRh3B2

We succeeded in growing single crystals of ferromagnets NdRh3B2 and GdRh3B2 with the hexagonal structure, and measured the electrical resistivity, specific heat, magnetic susceptibility and magnetization. From these measurements, the Curie temperature T-C is determined as T-C = 10.2K in NdRh3B2 and T-C = 93 K in GdRh3B2. The magnetic moments of about 2.5 mu(B) in NdRh3B2 and 7.7 mu(B) in GdRh3B2 are oriented in the basal plane. The crystalline electric field scheme is proposed for NdRh3B2 on the basis of the experimental results of Schottky anomaly in the specific heat and anisotropic susceptibility and magnetization. The Fermi surface in NdRh3B2 is very similar to that in a non-4f reference compound LaRh3B2, possessing the quasi-one dimensional electronic character.