Single-crystal growth of Tb0.4Y0.6Ni2B2C compounds by the floating-zone method

Single crystals of a Tb0.4Y0.6Ni2B2C intermetallic compound, which exhibit the coexistence of superconductivity and low-temperature magnetic ordering, have been grown by vertical floating-zone melting. The growth process of t hese intermetallic compound crystals is analysed from in situ tracking of t he zone temperature, segregation behaviour along the axis, and the constitu tion of the ultimate zone. The slight shift of composition along the crysta l axis, increase in Tb/(Tb + Y)-fraction but decrease in Ni/B ratio, were r evealed by electron probe microanalysis. The superconducting transition tem perature along the axis co-ordinate is nearly constant at T-c = 4.0 +/- 0.1 K with a transition range of Delta T-c = 0.8 K. Stacking faults resulting from a local deviation of the stoichiometric composition were found near th e end of the crystal by TEM investigations. (C) 2000 Elsevier Science B.V. All rights reserved.