Martensitic transformation in NiMnGa/Si bimorph nanoactuators with ultra-low hysteresis

Lambrecht, Franziska; Sagardiluz, N.; Gueltig, Marcel; Aseguinolaza, I. R.; Chernenko, V.A.; Kohl, Manfred

doi:10.1063/1.4984058

Cited by 12 publications

(8 citation statements)

References 15 publications

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“…The temperature dependence of the transition stress for loading and unloading processes is displayed in Figure (e), showing a decreasing hysteresis with increasing temperature that finally disappears at a critical stress. This is consistent with the previously analyzed phase diagram showing a weakening of the first order character of the transition that finally becomes a continuous second order transition, as observed in experiments . The black line in Figure (e) corresponds to the homogeneous equilibrium transition stress.…”

Section: Resultssupporting

confidence: 92%

“…The stress‐dependent strain, magnetization ( m x component), and temperature in the absence of a magnetic field are shown with black lines in Figure (a)–(c), respectively. From panel (a), notice that as σ increases, the first‐order character of the ferroelastic transition weakens and for a critical stress (indicated by the dotted lines) it finally becomes a second order one with the consequent suppression of hysteresis, in agreement with experimental observations . Again, σ < 0 ( σ > 0) permits both signs for m x ( m y ).…”

Section: Resultssupporting

confidence: 83%

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Multiferroic and Related Hysteretic Behavior in Ferromagnetic Shape Memory Alloys

Gebbia

Castán

Lloveras

et al. 2017

Physica Status Solidi (b)

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We combine a Ginzburg-Landau model for a ferroelastic transition with the theory of micromagnetism to study the magnetostructural behavior leading to multicaloric effects in ferromagnetic shape memory alloys. We analyze the ferroelastic transition under different conditions of temperature, stress and magnetic field and establish the corresponding phase diagram. On the one hand, our results show that the proper combination of both fields may be used to reduce the transition hysteresis and thus improve the reversibility of the related elastocaloric effects, superelasticity and stress-mediated magnetocaloric effects. On the other hand, the stress-free magnetic field-driven and thermally driven magnetostructural evolution provides physical insight into the low-temperature field-induced domain reorientation, from which we derive strategies to modify the operational temperature ranges and thus the corresponding (magnetic) shape-memory effect.

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Section: Resultssupporting

confidence: 92%

Section: Resultssupporting

confidence: 83%

Multiferroic and Related Hysteretic Behavior in Ferromagnetic Shape Memory Alloys

Gebbia

Castán

Lloveras

et al. 2017

Physica Status Solidi (b)

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“…On the other hand, the finite elements simulations conducted in Ref. enabled estimation of an average residual tensile stress in the film 6, which is also a part of cantilever in Figure , to be equal to about 300 MPa, the value being in line with the measured internal stresses in Ni–Mn–Ga/substrate thin films known from the literature . As matter of fact, this value of internal stress predetermines the temperature range, namely 340–420 K, where the nearly anhysteretic anomaly is observed in the right panel of Figure .…”

Section: Anhysteretic Behavior Of Ferromagnetic Sma Films and Nanobeamssupporting

confidence: 77%

“…The dependence reveals a strain change due to the two‐way shape memory effect via almost anhysteretic MT. Parallel measurements of the corresponding resistivity curves confirmed the temperature hysteresis width below 1 K . This remarkable deformational behavior is attributed to the close‐to‐postcritical state of the film and nanobeam, since it is feasible that the internal stress and temperature range of anomaly exceed the stress and temperature corresponding to the critical point in the phase diagram described in Sections 2 and 3.…”

Section: Anhysteretic Behavior Of Ferromagnetic Sma Films and Nanobeamsmentioning

confidence: 52%

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Large Anhysteretic Deformation of Shape Memory Alloys at Postcritical Temperatures and Stresses

Chernenko

L'vov

Kabra

et al. 2017

Physica Status Solidi (b)

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Magnetic and nonmagnetic shape memory alloys (SMAs) exhibit thermoelastic martensitic transformations (MTs) which are hysteretic due to their first-order nature. According to the thermodynamic Landau theory of phase transitions, which assumes ideal thermoelastic equilibrium at each point of the MT interval, the hysteresis is explained by the different limits of stability for austenite and martensite in the phase diagram. No interactions on the phase boundaries are taken into account. In the real alloys, the hysteresis of MT is related not only to the stability intervals of two phases but also to the processes of nucleation and growth of the resultant phase inside the parent phase. In turn, the features of these processes are related to the heights of energy barriers caused by the incompatibility of austenitic and martensitic lattices, crystal defects and some other physical factors. However, the defects, normally, play a minor role in the width of MT hysteresis if compared to the thermodynamic and crystallographic factors. A reduction of hysteresis of MT in SMAs, being crucial for technology, presents a challenging problem for science. A decrease of hysteresis width of MT was observed recently for the single crystals of ferromagnetic SMAs such Ni-Fe(Co)-Ga and Fe-Pd on approaching of their transformation paths to the critical point in stresstemperature phase diagram. Moreover, the superelastic and shape memory properties characterized by the nearly-zero hysteresis width were observed in the postcritical transformational regime. Here we show that both the Landautype theory of ferroelastic phase transitions and neutron diffraction experiments carried out under axial compression describe the essential features of these properties. We also interpret the experimentally observed anhysteretic phenomena in Ni-Mn-Ga thin films and nanobeam actuators in terms of their postcritical state.

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Mechanical response during bending of Ni–Mn–Ga-based melt-spun ribbons

et al. 2022

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In this paper, we report on mechanical properties observed during bending experiments conducted on quinary Ni–Mn–Ga–Co–Cu melt-spun ribbons. Depending on the ribbon’s side to which force is applied, different mechanical response is noted. Substantially larger mechanical instabilities are observed when force is applied to the “free side” than to the “wheel side” of ribbons. When force is applied to the latter, much lower force fluctuations are recorded and the amplitude of the force–displacement response remains within the experimental resolution limit. It is also shown that the character of the force–displacement curve changes upon cycling; mainly by decreasing the maximum force and mechanical hysteresis. These results are important for materials design and optimization of the magnetic field-induced bending effect recently shown in Ni–Mn–Ga-based melt-spun ribbons.

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Martensitic transformation in NiMnGa/Si bimorph nanoactuators with ultra-low hysteresis

Cited by 12 publications

References 15 publications

Multiferroic and Related Hysteretic Behavior in Ferromagnetic Shape Memory Alloys

Multiferroic and Related Hysteretic Behavior in Ferromagnetic Shape Memory Alloys

Large Anhysteretic Deformation of Shape Memory Alloys at Postcritical Temperatures and Stresses

Mechanical response during bending of Ni–Mn–Ga-based melt-spun ribbons

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