Low-temperature magnetic hardening and exchange anisotropy in nanocrystalline FeNbCrBCu alloys

Abstract The hysteresis loops of nanocrystalline Fe 73,5 Nb 4.5 Cr 5 B 16 Cu 1 alloys have been studied in a temperature range between 1.5 and 300 K. A magnetic hardening by nearly two orders of magnitude have been observed at temperatures below ∼50 K. The remarkable shift of the hysteresis loops detected at liquid helium temperatures after the field cooling as well as the strong irreversibility between zero-field cooling and field-cooling branches of magnetization curves indicate the presence of spin-disorder phase, which influences significantly the low-temperature behavior in the investigated nanocrystalline system.