Effect of magnetic field on the itinerant Co-subsystem in Ho 0.423 Y 0.577 Co 2

In order to study the band metamagnetism in the cubic Laves-phase compounds R1-xYxCo2 [R = rare earth], neutron-diffraction measurements of the Ho0.423Y0.577Co2 compound with yttrium content just below the critical value (xc=0.58) have been performed in an applied magnetic field of up to 2 T and in the temperature range from 4.2 to 22 K. It has been found that the small external magnetic field produces an ordering effect in the R-subsystem which is accompanied by an irreversible growth of the magnetization of the Co-sublattice.