Magnetic properties, magnetoresistance, and electronic structure of cubic DyCu5

The magnetic properties, magnetoresistance (MR), and electronic structure of the cubic phase (structure-type AuBe5, space group F-43m) of melt-spun DyCu5 have been investigated. In ac-susceptibility and magnetization measurements it has been found that below a critical temperature T-m = 7.5 K this phase is metamagnetic. alpha DyCu5 samples show a negative magnetoresistance ratio MR(H) = [R(H) - R(0)]/R( 0) of about -27% at 10 K and 5 T. This effect has similar behavior in transverse and perpendicular current-field directions. The electronic structure of alpha DyCu5 was calculated by the ab initio self-consistent spin-polarized tight-binding linear muffin tin orbital method in the atomic sphere approximation for the experimental value of lattice parameter a=0.7027 nm. The Fermi-level E-F is located at the minority 4f Dy band. The main contribution to the density of states at the E-F comes from 4f states of Dy and 3d states of copper atoms in one of two nonequivalent positions in a crystallographic cell. (C) 1999 American Institute of Physics. [S0021-8979(99)57608-1].