Magnetic structure of TbNi2B2C

Neutron-diffraction techniques have been used to study the magnetic structure of TbNi2B2C. The measurements, performed on single crystals of this compound, show that below approximately 15 K the moments order in an almost longitudinal spin wave with wave vector along a*. The magnitude of the wave vector is close to that obtained in the Ho, Er, and Gd compounds. This observation provides additional evidence that there are common Fermi-surface nesting features along a* in the rare-earth nickel boride carbides which cause the magnetic ordering of the rare-earth moments via the Ruderman-Kittel-Kasuya-Yosida mechanism. Below approximately 8 K, the experimental results indicate the development of a small ferromagnetic component. copyright 1996 The American Physical Society