Structural and magnetic stability of an amorphous Fe-based alloy with a wide supercooled liquid region

Abstract

The magnetic after‐effect of initial reluctivity in an amorphous Fe73Al5Ga2P10C5B4Si1 alloy has been investigated by isochronal as well as isothermal measurements. The relaxation intensity is lower than in simpler Fe‐based amorphous alloys prepared by rapid quenching methods. This is produced by reduced free volume quenched within the sample during manufacturing and by strong chemical bonds between metalloid atoms and atoms improving the glass‐forming ability of the alloy. Changes of pre‐exponential factor indicate large changes of amorphous structure after different heat treatments. Different relaxation mechanisms are identified in the samples, reorientation of atom pair axes and short‐range metalloid migrations leading to homogenization of the structure and reduction of the free volumes. The most probable activation energy Q* and pre‐exponential factor τ0 are lowest for as‐prepared samples: Q* = 1.42 eV and τ0 = 3 × 10−16 s. Both these quantities increase after annealing and slow cooling to Q* = 1.79 eV and τ0 = 2 × 10−15 s. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Structural relaxation and low-field magnetic properties of bulk amorphous ( 2 or 5) alloys

“…Lower maxima in the isochronal disaccommodation curves for thicker sample result from smaller free volumes concentration because they are annealed out during the ribbon preparation. It is in agreement with results obtained by Andrejco et al [2] and is connected with lower quenching rate in the production process of those ribbons. The isochronal disaccommodation curves were decomposed into three elementary processes, each of them being described with the Gaussian distribution of relaxation times [5].…”

“…Fe-(Al-Ga)-(P-C-B, Si, Ge) systems are the one group of alloys exhibiting a large glassforming ability. Andrejco et al [2] have stated that these alloys show lower disaccommodation intensity than the classical Fe-based amorphous materials. This paper is aimed at structural relaxations and low-field magnetic properties of the bulk amorphous Fe 75Àx Al 5 P 11 Ga x B 4 C 5 (x ¼ 0, 2 or 5) alloys.…”

Directional ordering in amorphous Co–Si–B alloys

“…The peak just below the Curie temperature is usually narrow, and originates from a ferromagnetic to paramagnetic phase transition. This description of a typical MAE spectrum holds for a wide variety of compositions, from binary (Co, Fe)-M, where M is a metalloid [2][3][4][5] through ternary and quaternary alloys [1,[6][7][8] to multicomponent systems [9]; hence some authors argue (see [10] and references therein) that the magnetic relaxation has a structural, rather than compositional nature.…”