SINGLE-CRYSTAL GROWTH OF R(3)CO (R-LA,PR AND ND) AND THEIR CHARACTERISTIC TRANSPORT-PROPERTIES

We succeeded in growing the single crystals of R(3)Co (R: La, Pr and N d), which possess the orthorhombic Fe3C type crystal structure. They w ere grown by the Bridgman method using a Tanman furnace with an alumin a crucible in high vacuumed quartz tube. The size of ingot was 1.0 x 1 0(-2) m in diameter and 2.0 x 10(-2) m in length. For single crystalli ne La3Co, we observed the saturation phenomena in the electrical resis tivity. The T-2 dependence is observed below 20 K in the electrical re sistivity, whose coefficient A is 2.9 x 10(-10) Ohm m/K-2. The gamma v alue of La3Co shows a fairly large value of 25 x 10(-3) J/K(2)mol. We underline that the normal state of La3Co is characterized by the uncon ventionality of A/gamma(2) value of 0.46 x 10(-6) Ohm nm (Kmol/J)(2). For single crystalline Pr3Co, we also found the saturation phenomena a nd the TZ dependence in electrical resistivity. The coefficient A of 3 .1 x 10(-10) Ohm m/K-2 is close to that of La3Co. It suggests that the 3d band of cobalt plays an important role in the transport properties of R(3)Co compounds.