Magnetic properties and crystallization of Co68Mn10B10Si12 and Co58Mn20B10Si12 amorphous alloys

Crystallization and structural relaxation of Co48Mn20Ge10B10Si12 amorphous alloy

“…1-3, it can be concluded that, like other Co-rich amorphous alloys [3,7,8], Co 48 Mn 20 Ge 10 B 10 Si 12 devitrified through a primary crystallization, in which metal-rich crys- talline phases first nucleated, followed by eutectic reaction triggered by the metalloid enrichment of the matrix [9]. This amorphous alloy, however, unlike other Co-rich compositions, showed a substantial irreversible change in magnetic properties when annealed below the crystallization temperature.…”

“…1. We have previously observed that when amorphous alloys containing similar amounts of Co and Mn were annealed, in some cases, the Co 2 MnSi phase formed at the incipient stage of crystallization was metastable and decomposed at higher annealing temperatures [3]. The Co 2 Mn(Si,Ge) phase in this alloy was stable so that there was a substantial amount of Co 2 Mn(Si,Ge) even after full devitrification.…”

“…However, the observed increase in magnetic moment for those alloys was minimal (∼10% increase), as compared with the alloy shown here. It is also noted that Co-Mn alloys fabricated without Ge did not show any evidence of structural relaxation prior to devitrification [3].…”

“…In the study, during crystallization of Co 78−x Mn x B 10 Si 12 , we observed formation of Co 2 MnSi, which is one of Heusler alloys that has been extensively studied due to its predicted half-metallic property with 100% spin polarization [5]. However, the formation of Co 2 MnSi was immediately followed by nucleation of crystalline Co as annealing temperature was increased [3].…”

“…Especially, transition metal-metalloid amorphous magnetic alloys containing Fe, Ni, and Co were intensively studied due to their soft magnetic properties such as low coercivities, low hysteresis loss, and high permeabilities combined with excellent mechanical properties [2]. In our previous work [3,4], we introduced Mn into Co-rich amorphous alloy in order to study the influence of structural disorder on the magnetic state and crystallization behavior of the Co-Mn amorphous alloys. In the study, during crystallization of Co 78−x Mn x B 10 Si 12 , we observed formation of Co 2 MnSi, which is one of Heusler alloys that has been extensively studied due to its predicted half-metallic property with 100% spin polarization [5].…”