Magnetic properties of bulk amorphous Ho4Fe3

The magnetic properties of a-Ho
4
Fe
3
ribbons are investigated from 4.2 K to 300 K in permanent magnetic fields up to 140 kOe. The paramagnetic-magnetic ordered state transition temperature is found to be T
c
= 140 K. "Re-entrant" transition from magnetic ordered to spin-glass-like state is observed at 55 K. The number of magnetic peculiarities as: strong magnetic dependent Hopkinson effect, high coercivity at low temperatures (H
c
= 6 kOe at 4.2 K), large magnetic aftereffect and paraprocess are typical of the later state. The magnetic behavior of the alloy investigated is compared with that of a-Ho
4
Co
3
alloy investigated recently.