Anomalous magnetic behavior in half-metallic Heusler Co2FeSi alloy glass-coated microwires with high Curie temperature

In the current study, we have succeeded to fabricate Co2FeSi Heusler alloy glass-covered microwires with magnetic core nucleus diameter d = 4.36 mu m and total diameter D = 17.55 mu m, with high Curie temperature (T-e > 1100 K) and well-defined magnetic anisotropy for high temperature spintronic devices application. The magnetic properties of as-prepared and annealed at different temperature (873 K, 973 K and 1073 K for 1 h) of Co2FeSi Heusler alloy glass-covered microwires have been investigated. Strong dependence of the magnetic properties on the annealing conditions has been indicated. Anomalous magnetic behavior for annealed samples at 873 K and 973 K has been found and structural properties of such samples have been analyzed. Critical temperatures 155 K and 250 K have been detected for annealed samples at 873 K and 973 K, respectively, where the behavior of M-H loops and coercivity changed. Below the critical point the M -H curve shows kink or wasp-waisted magnetic behavior and complex magnetic reversal mechanism is supposed. The anomalous magnetic behavior is due to the martensitic phases induced by annealing con-ditions below the room temperature. This unusual magnetization behavior provides opportunities to un-derstand the phenomena of different types of magnetic domain structures in the preferred crystallographically oriented Co2FeSi Heusler alloy glass-coated micro-wires, essentially helpful for de-signing the devices based on magnetization switching. (c) 2022 The Authors. Published by Elsevier B.V. CC_BY_NC_ND_4.0

Automated summary

In this study, Co2FeSi Heusler alloy glass-covered microwires were successfully fabricated and their magnetic properties were investigated. The annealing conditions were found to have a strong influence on the magnetic behavior of the samples. Anomalous magnetic behavior was observed in the annealed samples, and the structural properties were analyzed. These findings are important for the design of devices based on magnetization switching.