Acoustic-assisted magnetic-field-induced strain and stress output of Ni–Mn–Ga single crystal

Abstract

Articles you may be interested indc-and ac-magnetic field-induced strain effects in ferromagnetic shape memory composites of Ni-Mn-Ga single crystal and polyurethane polymer J. Appl. Phys. 107, 09A942 (2010); 10.1063/1.3357408 Large magnetic-field-induced strains in Ni-Mn-Ga nonmodulated martensite Appl. Phys. Lett. 95, 104103 (2009); 10.1063/1.3227661Acoustic-assist effect on magnetic threshold field and twinning-yield stress of Ni-Mn-Ga single crystals

Frequency response of acoustic-assisted Ni–Mn–Ga ferromagnetic-shape-memory-alloy actuator

“…The load amplitude of the actuator without acoustic assistance at low frequency (10 Hz) is calculated to be 7.95 N or 0.99 MPa. The resulting load corresponds well with the previous report [17] that, under quasi-static actuation, the stress output from FSMA actuators is typically limited in the range between 0.8 -1.5 MPa, because the magnetic energy that is coupled into a material is limited by the anisotropy energy, K u .…”

“…It is also reported that the cyclic reversible strain of the Ni-Mn-Ga single crystal increases from 0.03 to 0.045 with an acoustic-assist technique. The larger strain appears over a broader range of stress output [17]. As a result, the acoustic-assist technique is shown to increase the efficiency of an FSMA device in delivering mechanical energy σ bias ε out .…”

“…Consequently, the magnetic stress output may increase if the operating temperature is much lower than the Curie We report a means to reduce the required threshold field and increase the strain output at room temperature without altering the FSMA dimensions or reducing its temperature. It has been reported that application of an acoustic wave (from a piezoelectric stack transducer) with an appropriate polarization, to the Ni-Mn-Ga single crystal during the MFIS actuation at low frequencies (≤ 1 Hz) can result in a reduction of the threshold field by up to 0.5 kOe and a significant increase in the strain output depending on the magnetic field [16][17][18]. It is also reported that the cyclic reversible strain of the Ni-Mn-Ga single crystal increases from 0.03 to 0.045 with an acoustic-assist technique.…”

Magnetic-Field-Induced Effects in Martensitic Heusler-Based Magnetic Shape Memory Alloys

“…The high-temperature limit is usually imposed by the transition temperature of the reverse martensitic transition. The presence of an acoustic drive has been proposed in order to improve twin-boundary mobility thus making the magnetic shape memory effect more efficient (Techapiesancharoenkij et al, 2008a). It was shown that a small amplitude acoustic signal generated by means of a piezoelectric actuator is suitable to reduce the threshold field and to achieve greater strains under a smaller magnetic field.…”

Temperature dependent damping studies of Ni-Mn-Ga polymer composites

“…It is evident from the literature that the FSMAs have ferromagnetic nature and undergo martensite transformation (Ullakko et al 1996;Mullner and Ullakko 1998;Mullner et al 2002;Chernenko et al 2007;Techapiesancharoenkij et al 2008). The phase transformation and energy dissipation through twin mechanism in Ni-Mn-Ga makes it a suitable candidate for dampers.…”