The complex magnetic ordering of TbNi2B2C and Tb0.4Y0.6Ni2B2C single crysta
ls has been investigated by AC-susceptibility and magnetization measurement
s. Metamagnetic transitions and an anisotropic behavior within (a, b)-plane
were revealed for TbNi2B2C. Alloying with Y reduces the critical field of
antiferromagnetic to paramagnetic transition, eliminates the metamagnetic t
ransitions and induces superconductivity below 4.1 K. (C) 2000 Elsevier Sci
ence B.V. All rights reserved.