Magnetic after-effect in FeNiZrCuB amorphous alloys

The magnetic after-effect (MAE) and AC susceptibility in the amorphous Fe86 -xNixZr7Cu1B6 alloys with different contents of Ni (x = 0-86 at%) were inve stigated. The Curie temperatures T-c were estimated from the temperature de pendences of the AC susceptibility measured in the temperature range 20-550 degrees C. Additions of Ni up to x = 43 at% cause rapid increase of the Cu rie temperature from 71 degrees C for Fe86Zr7Cu1B6 to 373 degrees C for Fe4 3Ni43Zr7Cu1B6 alloys. Higher concentrations of Ni cause decrease of T-c dow n to paramagnetic state of Ni86Zr7Cu1B6 alloy at the room temperature. It w as found that the additions of Ni drastically change shapes and amplitudes of MAE spectra. From the MAE spectra measured in the temperature ranges (-1 97 degrees C; T-c) the activation energy spectra with the most probable val ue Q = 1.23 eV were obtained. (C) 1999 Elsevier Science B.V. All rights res erved.