Structure–Property Relationships for Weak Ferromagnetic Perovskites

Despite several decades of active experimental and theoretical studies of rare-earth orthoferrites, the mechanism of the formation of their specific magnetic, magnetoelastic, optical, and magneto-optical properties remains a subject of discussion. This paper provides an overview of simple theoretical model approaches to quantitatively describing the structure–property relationships—in particular, the interplay between FeO6 octahedral deformations/rotations and the main magnetic and optic characteristics, such as Néel temperature, overt and hidden canting of magnetic sublattices, magnetic and magnetoelastic anisotropy, and optic and photoelastic anisotropy.

Development of Magnetic Microwires for Magnetic Sensor Applications

Thin magnetic wires can present excellent soft magnetic properties (with coercivities up to 4 A/m), Giant Magneto-impedance effect, GMI, or rectangular hysteresis loops combined with quite fast domain wall, DW, propagation. In this paper we overview the magnetic properties of thin magnetic wires and post-processing allowing optimization of their magnetic properties for magnetic sensor applications. We concluded that the GMI effect, magnetic softness or DW dynamics of microwires can be tailored by controlling the magnetoelastic anisotropy of as-prepared microwires or controlling their internal stresses and domain structure by appropriate thermal treatment.

Impact of Stress Annealing on the Magnetization Process of Amorphous and Nanocrystalline Co-Based Microwires

The domain wall (DW) dynamics of amorphous and nanocrystalline Co-based glass-coated microwires are explored under the influence of stress annealing. Different annealing profiles have enabled remarkable changes in coercivity and magnetostriction values of Co-based amorphous microwires with initially negative magnitude, allowing induced magnetic bistability in stress-annealed samples and, consequently, high DW velocity has been observed. Similarly, Co-based nanocrystalline microwires with positive magnetostriction and spontaneous bistability have featured high DW velocity. Different values of tensile stresses applied during annealing have resulted in a redistribution of magnetoelastic anisotropy showing a decreasing trend in both DW velocities and coercivity of nanocrystalline samples. Observed results are discussed in terms of the stress dependence on magnetostriction and microstructural relaxation.

Engineering of giant magnetoimpedance effect of amorphous and nanocrystalline microwires

We present our studies of the factors affecting soft magnetic properties and giant magnetoimpedance effect in thin amorphous and nanocrystalline microwires. We showed that the magnetoelastic anisotropy is one of the most important parameters that determine magnetic softness and GMI effect of glass-coated microwires and annealing can be very effective for manipulation the magnetic properties of amorphous ferromagnetic glass-coated microwires. Considerable magnetic softening and increasing of the GMI effect is observed in Fe-rich nanocrystalline FINEMET-type glass-coated microwires after the nanocrystallization.

Components of Magnetic Anisotropy of Soft Magnetic Nanocrystalline Fe-Based Films

We present quantitative evaluation results of micromagnetic structure parameters of nanocrystalline Fe, Fe95Zr5, Fe90N10, and Fe85Zr5N10films obtained by magnetron sputtering. It is shown that quantities of magnetocrystallineK1, magnetoelasticKME, magnetostaticKMS, and surfaceKa,Sanisotropies are components of experimentally measured effective local anisotropyKeff. The shape of the hysteresis loops of the films is determined by the presence of two main macroscopic effective magnetic anisotropies, one of which is the anisotropy field of stochastic domains, and the other is the magnetoelastic anisotropy field due to residual macrostresses.