Magnetic-Field Induced Two-Way Shape Memory Effect of Ferromagnetic Ni&lt;SUB&gt;2&lt;/SUB&gt;MnGa Sputtered Films

Ohtsuka, Makoto; Konno, Yu; Matsumoto, M.; Takagi, Toshiyuki; Itagaki, Kimio

doi:10.2320/matertrans.47.625

Cited by 10 publications

(6 citation statements)

References 20 publications

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“…Concerning actuation and resetting, also other options exist, such as the use of two counteracting FSMA film actuators, the design of FSMA films showing the two‐way shape memory effect, or the use of a FSMA film composite comprising an additional elastic layer. The different options of combined use of film‐based actuation and energy harvesting are summarized in Table 1 .…”

Section: Methods Of Thermal Energy Harvesting By Magnetic Sma Filmsmentioning

confidence: 99%

High Frequency Thermal Energy Harvesting Using Magnetic Shape Memory Films

Gueltig

Oßmer

Ohtsuka

et al. 2014

Advanced Energy Materials

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optical, medical and lab-on-chip systems including mobile, wearable and implantable devices. [ 5 ] Various concepts for energy harvesting on a miniature scale have been developed in the past based, e.g., on piezoelectric, [ 1,6 ] electromagnetic induction, [ 7 ] electrostatic, [ 8 ] and thermoelectric principles. [ 9 ] In the fi rst three cases, kinetic energy is generated by using vibration in the environment. These systems are commonly based on electromechanically coupled spring-damper systems.Thermoelectric principles use temperature gradients in the environment to produce electrical power (Seebeck effect). In contrast to the aforementioned principles, no moving parts are required. While being versatile for various applications, they face a number of diffi culties when it comes to miniaturization. The effi ciency of thermoelectric devices is determined by the fi gure of merit ZT , which is in the order of 1 in best cases. [ 10 ] In order to obtain a reasonable output, relatively large temperature differences Δ T and means of heat sinking beyond natural convection are required. [ 11 ] In small dimensions, however, Δ T is reduced and, thus, energy conversion becomes ineffi cient.For the use of energy resources stored at small Δ T below 20 K, smart materials showing a fi rst order phase transformation without diffusion are highly attractive. Recent developments on MSMAs demonstrate abrupt changes in lattice parameters beyond 10% and corresponding large changes in their magnetic properties (magnetization, magnetic anisotropy) at small Δ T . [12][13][14][15][16][17] Owing to their multifunctional properties, these materials may perform different tasks while keeping the design simple, which is important for downscaling. Due to these reasons, magnetic SMAs are predestined for thermal microenergy harvesting.Recently, a new series of magnetic SMA systems, Ni-Mn-X-Y (X: In, Sn, Sb, Y: Co, Fe) has been found showing a fi rst order phase transformation with a large change of magnetization Δ M . [14][15][16][17] Ni-Mn-In and Ni-Co-Mn-In alloys show a particularly drastic Δ M effect due to a martensitic transition from a ferromagnetic austenite phase to a nonferromagnetic martensite phase. [ 18,19 ] An important prerequisite for energy conversion in a cyclic process are highly reversible phase transformations. The stress associated with the change of lattice parameters during phase transformation can cause pronounced microstructural changes including the formation of dislocations and other A new method for thermal energy harvesting at small temperature difference and high cycling frequency is presented that exploits the unique magnetic properties and actuation capability of magnetic shape memory alloy (MSMA) fi lms. Polycrystalline fi lms of the Ni 50.4 Co 3.7 Mn 32.8 In 13.1 alloy are tailored, showing a large abrupt change of magnetization and low thermal hysteresis well above room temperature. Based on this material, a free-standing fi lm device is designed that exhibits thermomagnetically induced actuation between a hea...

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Section: Methods Of Thermal Energy Harvesting By Magnetic Sma Filmsmentioning

confidence: 99%

High Frequency Thermal Energy Harvesting Using Magnetic Shape Memory Films

Gueltig

Oßmer

Ohtsuka

et al. 2014

Advanced Energy Materials

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“…(13) Sputtering is one of the methods used for preparing an MSMA thin film. (14)(15)(16)(17) Sputtering makes it possible to fabricate thin films with a thickness of several microns, which is difficult with bulk materials. In addition, it is expected to contribute to improving the response in actuation and the downsizing of actuators.…”

Section: Introductionmentioning

confidence: 99%

Metamagnetic Shape Memory Alloy Thin Plates Consolidated by Compression Shearing Method at Room Temperature for Thermal Energy Harvesting Device

Miki¹,

Eijiro²,

Takeda

et al. 2020

Sensors and Materials

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As a powder metallurgy technique, the compression shearing method at room temperature (COSME-RT) is used for making metamagnetic shape memory alloy (MSMA) thin plates. COSME-RT is a method for consolidating a thin plate from powder raw material by a certain dynamic process that simultaneously applies a compression stress and a shearing strain to a powder material at room temperature and in ambient atmosphere. A plate of 50 μm thickness fabricated by COSME-RT using Ni-Co-Mn-In powder from ground sputtered film is cut into 2 × 2 × 0.05 mm 3 and then applied to a thermal energy harvesting device. This device generates an average power density of 68 μW•cm −3 and a peak power of 0.95 mW•cm −3 , which makes it possible to supply a small amount of electric power to a certain type of sensor or small sensor device.

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“…Fig. 3 shows the shape change under the magnetic field of 0 and 5 T and the strain-magnetic field curve at the temperature between M s * and M f * on cooling for the N54.4(AG) film with the large gradient and small thermal hysteresis in the strain-temperature curve [7]. The strain increased with increasing magnetic field and decreased with decreasing magnetic field.…”

mentioning

confidence: 96%

“…The strain-temperature curves under the magnetic field of 0 and 5 T for N51.4(AG) and N54.4(AG) films are shown in Fig. 1 [7]. The strain at the outer surface was given by e ¼ d/2r, where d is the thickness of the films and r is the radius of a curvature for the films.…”

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confidence: 99%