Magnetic properties of DyB2C, HoB2C, and ErB2C -: art. no. 064433

Magnetic properties of layered borocarbides RB2C (R=Dy, Ho, and Er) have been studied by the magnetization and specific heat measurements at 1.8-300 K under the field up to 5 T. ErB2C has a basic two-sublattice antiferromagnetic order below T-N=16.3 K. HoB2C and DyB2C show the three-dimensional magnetic order below T-C=7.0 K and 8.5 K, respectively. However, they have still large magnetic fluctuations below T-C. The magnetic ordering temperatures of RB2C (R=Dy, Ho, and Er) do not follow the de Gennes relation, where the ordering temperatures of HoB2C and DyB2C are suppressed. The suppressions of ordering temperature and the unconventional fluctuating ground states of HoB2C and DyB2C originate from the spin frustration effects. The instability of the unconventional magnetic phase associated with the frustration is significant in this series; the fluctuating ground state results from the complex spin-spin interactions or spin-quadrupole interactions.