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The structural and magnetic properties of amorphous ferromagnetic microwires can undergo significant measurements under the action of external mechanical stresses and heat treatment. The study of transformations occurring in this case is important for designing various sensors of mechanical stresses, loading, and temperature and also for inducing in the wires a certain type of magnetic anisotropy that plays a significant role in the realization of various effects in them. In this work, the influence of external stresses and annealing on the processes of the magnetization and the magnetic impedance of Co71Fe5B11Si10Cr3 microwires having a low positive magnetostriction (~10-8) in amorphous state has been studied. The influence of external stresses leads to a sharp change in the character of the magnetization reversal curve, which was due to the change in the sign of the magnetostriction and the type of magnetic anisotropy. The amplitude of higher harmonics and the value of the magnetic impedance, respectively, are sensitive to mechanical stresses. Elastic stresses in the wires with a partial crystallization do not lead to a marked change in the magnetic properties; however, annealing can lead to a substantial increase in the axial magnetic anisotropy of the wires existing in the stressed state. The experimental results are analyzed in the framework of a magnetostriction model of induced magnetic anisotropy. [ABSTRACT FROM AUTHOR]

Various thermal treatments have long been known to be effective in tailoring structural and magnetic properties of amorphous ferromagnetic wires, consequently, a desired magnetic anisotropy can be controlled for specific sensing applications. This paper deals with the effects of annealing and applied stresses on the magnetization processes and magnetoimpedance (MI) in Co71Fe5B11Si10Cr3 glass-coated microwires having amorphous or partially crystalline structure. The alloy under study has a small positive magnetostriction (approximately 10^-8 ) in its amorphous unstressed state. By applying a tensile stress to amorphous microwires, an abrupt transformation of the hysteresis loop is observed owing to the anisotropy type change due to stress-dependent magnetostriction which changes sign. The modification in the anisotropy type greatly enhances the stress sensitivity of higher frequency harmonics induced during re-magnetization and MI. The wires with a partially crystalline structure did not exhibit a noticeable stress dependence of magnetic properties, but after annealing a significant increase in coercivity was observed after applying a tensile stress. The obtained results were investigated in terms of a magnetostrictive model of magnetic anisotropy offering a reasonable explanation. [ABSTRACT FROM AUTHOR]