Magnetomechanical damping and magnetoelastic hysteresis in permalloy

Abstract

The inverse Wiedemann effect (IWE) consisting in longitudinal magnetization reversals was detected with a cylindrical permalloy layer subjected to circular DC magnetic fields while performing low frequency (∼1 Hz) free torsion oscillations. Hysteresis occurring in the magnetization vs elastic strain dependence (the `magnetoelastic hysteresis') suggested irreversible processes activated mechanically. Joint vibration and magnetization time records were carried out by means of an experimental set-up including inverted pendulum and conventional integrating fluxmeter, in order to compare the relative energy losses ascribed to the magnetomechanical damping (MMD) and to the magnetoelastic hysteresis, respectively. The experimental results clearly pointed out a close connection between IWE and MMD providing evidence that, when simultaneously examined, both effects reflect the same basic phenomenon: the irreversible magnetization changes induced by the elastic strain.

The influence of the magnetic field on the elastic properties of anisotropic magnetorheological elastomers

“…As their mechanical and rheological properties are well controlled by applied magnetic fields, these materials are of interest in various applications. Unlike the MRSs, in which long term particles deposition often occurs [1][2][3][4] the stability of the MREs is ensured by inserting the particles in polymer chains [5][6][7][8][9][10][11][12][13][14]. The capabilities of MREs have received an increasing interest cluring last decades.…”

“…These MREs' properties are used in various systems. Thus, Deng et al [7] proposed magnetomechanical damping devices based on adaptive tuned vibrations (note that the damping mechanism in MREs differs from that in magnetostrictive materials [8,9]). …”

Magnetomechanical damping in stress-relieved Ni: the effect of the dc magnetic field

“…The IF was measured at frequencies close to 1 Hz under torsional vibrations in free decay, by means of an inverted pendulum using a tungsten wire, 0.1 mm in diameter, as elastic suspension. The angular deflection of the pendulum was converted into a voltage by means of a Hall effect-based transducer with a resolution better than 6 × 10 −4 rad; details are given elsewhere [36]. During vibrations a dc magnetic field was applied longitudinally in equal steps of 508 A m −1 ; the field strength was maintained constant until motion extinction and then in situ ac demagnetization was performed prior to the next vibration initiation.…”

Characterization and Modeling of Dynamic Sensing Behavior in Ferromagnetic Shape Memory Alloys

“…On the other hand, the flux density dependence on strain shows a monotonic increase in hysteresis with increasing frequency. The hysteresis loss in the stress versus strain plots is equal to the area enclosed by one cycle ( σdε), whereas the loss in the flux density versus strain plots is obtained by multiplying the enclosed area ( Bdε) by a constant that has units of magnetic field [16,17]. Fig.…”