Magnetic anisotropy and stress-magnetoimpedance (S-MI) in current-annealed Co-rich glass-coated microwires with positive magnetostriction

• Published in: Journal of magnetism and magnetic materials Vol. 474; pp. 296 - 300
• Main Authors: Nematov, M.G., Adam, A.M., Panina, L.V., Yudanov, N.A., Dzhumazoda, A., Morchenko, A.T., Makhnovskiy, D.P., Qin, F.X.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.03.2019; Elsevier BV
• Subjects: Anisotropy; Annealing; Co-based magnetic wires; Coating effects; Current annealing; Giant magnetoimpedance; Glass; Hysteresis; Inflow; Magnetic anisotropy; Magnetic fields; Magnetic hysteresis loop; Magnetic properties; Magnetoimpedance; Magnetostriction; Stress-magnetoimpedance (S-MI); Tensile stress; Stress-magnetoimpedance (S-MI); Current annealing; Giant magnetoimpedance; Magnetic hysteresis loop; Co-based magnetic wires
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2018.11.042

•Current annealing induces circular magnetic anisotropy in amorphous microwires with positive magnetostriction.•Induced anisotropy is sensitive to mechanical stress.•Current annealing and tensile stress act in opposite way with respect to the easy anisotropy.•Stress sensitivity of impedance of more than 260% for 250 MPa is realized with bias fields. Effects of a dc current annealing, in terms of magnitude and inflow time, on magnetic hysteresis properties, magnetoimpedance (MI) and stress-magnetoimpedance (S-MI) in glass-coated amorphous Co71Fe5B11Si10Cr3 microwires with a small positive magnetostriction were investigated in this work. The annealing process combining Joule-heating and circular magnetic field leads to the creation of a specific magnetic anisotropy of a helical or circular type, and consequently, is helpful to control the MI and S-MI behaviours making them more suitable for particular sensing applications. After annealing, the magnetoimpedance plots transformed from a bell-shaped typical of an axial easy anisotropy to the shape with two symmetrical peaks, the magnitude and position of which are controlled with the annealing current parameters. Applying a tensile stress on the annealed wires changes the easy anisotropy direction which leads to the potential for highly sensitive S-MI without use of dc bias fields. A stress sensitivity of more than 260% at σex= 250 MPa at zero magnetic field is achieved.