Interaction between magnetic order and the vortex lattice in HoNi2B2C

Local Hall probe array magnetization measurements have been made on single crystals of the magnetic superconductor HoNi2B2C. Measured flux profiles sh ow that surface barriers dominate the hysteresis below T-c(similar or equal to 8.9K) except in a narrow temperature range between 5 and 5.75 K where s uperconductivity is strongly suppressed due to the onset of an a-axis incom mensurate ordering of the Ho moments. The data presented show that the magn etic order also has a profound influence on the nonequilibrium (vortex-pinn ing) properties of the superconducting state.