Narrow Results

The magnetic properties and giant magnetostriction effect (GMS) of the amorphous alternant [Tb/Fe/Dy]_n (named S1) and [Fe/Tb/Fe/Dy]_m (named S2) nano-multilayer films have been studied. The magnetic hysteresis loops show that easy magnetic direction changes from perpendicular to the film plane (S1) to parallel to the film plane (S2). S2 has better soft magnetic properties and low-field giant magnetostriction effect than that of S1, due to the exchanging interaction between the hard GMS layer and the soft layer Fe. The different magnetic behavior is explained by considering the nature of the magnetization process, i.e. domain-wall motion and spin rotation.

The effect of annealing temperature on the magnetic and giant magnetostriction (GMS) of [Fe/Tb/Fe/Dy]_n multilayer films were investigated. X-ray diffraction showed that the multilayer films' microstructures were still in amorphous at annealing temperature 300°C. The multilayer films began to crystalline at annealing temperature 400°C. The saturation magnetization of multilayer films increased by the increasing annealed temperature. The coercivity first decreased at annealing temperature 300°C and then increased when the annealing temperature was higher than 400°C. The multilayer films had good low-field GMS, and the magnetostriction of the multilayer films increased by the increasing annealing temperature.

The current investigation examines the vibrational properties of porous truncated conical structures made from a composite material consisting of polyvinylidene fluoride (PVDF) reinforced with Terfenol-D particles. The effective properties of the magneto-electro-elastic composite were determined using the Eshelby–Mori–Tanaka model. The governing equation of the system is obtained by applying the principles of minimal potential energy and Hamilton’s principle to the first-order shear deformation theory. The equations are solved utilizing the generalized differential quadrature technique. This study aims to examine the interconnections among the volume percentage, vertex angle, shell length, boundary conditions, and porosity of Terfenol-D. Moreover, to validate the results, a comprehensive analysis was performed by comparing them with the existing body of literature, resulting in a favorable and accurate agreement. The results demonstrate a consistent decrease in the linear natural frequency as the vertex angle gradually increases. The findings derived from this study have the potential to serve as a reference point for future analyses.

Stress induced magnetic field changes in epoxy-based Terfenol-D composite materials offer a unique way for stress sensing by using a remote magnetic field sensor. In this paper, we report simultaneous measurements of the stress, strain and emitted magnetic field during compressive tests performed at different temperatures in the range of $-5^{\circ }$C–65${}^{\circ }$C. The observed results are explained based on the physical processes that occur at different stresses and temperature ranges. Measurement results reveal a temperature range ($-5^{\circ }$C–45${}^{\circ }$C) suitable for stress sensing applications, at which the reverse magnetostrictive response is almost temperature insensitive. At 65${}^{\circ }$C, the epoxy demonstrated a significant softening due to the glass transition, indicating that a high glass transition temperature is an important desired property for the epoxy matrix.

The axial periodic vibration of a giant magnetostrictive rod in the periodic altering magnetic field and the temperature field is analyzed in this paper. The mathematical model is established by the variational method, and the quadratic nonlinear mechanic-magnetic constitutive relationship is applied. The displacement solution and the relationship between the amplitude and the frequency are obtained by the harmonic method under the linear spring constrained boundary condition.