Stress modulated martensitic transition and magnetocaloric effect in hexagonal Ni2In-type MnCoGe1−xInx alloys

Liu, Yan; Shen, Fang; Zhang, M.; Bao, Li-Fu; Wu, Rongrong; Zhao, Yingying; Hu, Fengxia; Wang, J.; Zuo, Wenlong; Sun, J. R.; Shen, Baogen

doi:10.1016/j.jallcom.2015.07.234

Cited by 27 publications

(14 citation statements)

References 31 publications

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“…A unique feature of the present materials is their high sensitivity to stress. It has been found that an applied hydrostatic pressure can largely shift the magnetostructural transition to lower temperature1521 at a rate of 10K/kbar for Mn 0.93 Cr 0.07 CoGe, and a purposely introduced residual strain in a thin slice of MnCoGe 1−x In x can also be able to induce the possible appearance of a considerable amount of hexagonal phase that lost the martensitic structural transformation while the grain size keeps nearly unchanged28. All these demonstrate the key role of the change of interior stress and/or the introduced residual strain on the evolution of magnetostructural transition.…”

Section: Discussionmentioning

confidence: 99%

Critical dependence of magnetostructural coupling and magnetocaloric effect on particle size in Mn-Fe-Ni-Ge compounds

Shen

et al. 2016

Sci Rep

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Magnetostructural coupling, which is the coincidence of crystallographic and magnetic transition, has obtained intense attention for its abundant magnetoresponse effects and promising technological applications, such as solid-state refrigeration, magnetic actuators and sensors. The hexagonal Ni2In-type compounds have attracted much attraction due to the strong magnetostructural coupling and the resulted giant negative thermal expansion and magnetocaloric effect. However, the as-prepared samples are quite brittle and naturally collapse into powders. Here, we report the effect of particle size on the magnetostructural coupling and magnetocaloric effect in the Ni2In-type Mn-Fe-Ni-Ge compound, which undergoes a large lattice change across the transformation from paramagnetic austenite to ferromagnetic martensite. The disappearance of martensitic transformation in a large amount of austenitic phase with reducing particle size, to our best knowledge, has not been reported up to now. The ratio can be as high as 40.6% when the MnNi0.8Fe0.2Ge bulk was broken into particles in the size range of 5~15 μm. Meanwhile, the remained magnetostructural transition gets wider and the magnetic hysteresis becomes smaller. As a result, the entropy change drops, but the effective cooling power RCeffe increases and attains to the maximum at particles in the range of 20~40 μm. These observations provide constructive information and highly benefit practical applications for this class of novel magnetoresponse materials.

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Section: Discussionmentioning

confidence: 99%

Critical dependence of magnetostructural coupling and magnetocaloric effect on particle size in Mn-Fe-Ni-Ge compounds

Shen

et al. 2016

Sci Rep

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“…The introduced residual strain and defects during pulverization (Wu et al, 2016) or cold pressing (Liu et al, 2015) can also affect the magnetostructural coupling besides hydrostatic pressure. It has been reported that the introduced residual strain in the MnCoGe 1−x In x thin slices prepared by cold pressing can stabilize the austenite phase, as a result, the temperature window of martensitic transformation is broadened, the magnetic and structural transition becomes decoupling (Liu et al, 2015). Similarly, with reducing particle size, austenitic phase becomes stable and a high fraction of austenitic phase loses the martensitic transformation, and retains the hexagonal FM structure in the entire temperature range.…”

Section: Ni2in-type Mm'x Compoundsmentioning

confidence: 99%

Negative Thermal Expansion in the Materials With Giant Magnetocaloric Effect

Shen

Hao

et al. 2018

Front. Chem.

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Negative thermal expansion (NTE) behaviors in the materials with giant magnetocaloric effects (MCE) have been reviewed. Attentions are mainly focused on the hexagonal Ni2In-type MM'X compounds. Other MCE materials, such as La(Fe,Si)13, RCo2, and antiperovskite compounds are also simply introduced. The novel MCE and phase-transition-type NTE materials have similar physics origin though the applications are distinct. Spin-lattice coupling plays a key role for the both effect of NTE and giant MCE. Most of the giant MCE materials show abnormal lattice expansion owing to magnetic interactions, which provides a natural platform for exploring NTE materials. We anticipate that the present review can help finding more ways to regulate phase transition and dig novel NTE materials.

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“…And even in the temperature range far below MT temperature T t , e.g., 170 K for BM-0.5h sample, the austenite can still be observed (Figure a and Figure ). This should be responsible for the obvious broadening of the FMT temperature interval, and accordingly the widened Δ T of NTE, for the BM-0.5h sample in comparison with the bulk (inset of Figure a). ,, …”

Section: Results and Discussionmentioning

confidence: 96%

“…Evidently, the strain value increases with the elongation of BM time. It is well-known that the FMT is very closely related to the stress. ,,,, For bulk samples, annealing induces the stress release and structural relaxation, which produce the sharp FMT and accordingly narrow FMT temperature interval (inset of Figure a). , For BM samples, the uneven distribution of RS enforces the defects involved redistribution in the grain and grain boundaries and stabilizes the hexagonal austenite, pushing MT to lower temperature. ,, A certain proportion of austenite loses MT with temperature reducing . And even in the temperature range far below MT temperature T t , e.g., 170 K for BM-0.5h sample, the austenite can still be observed (Figure a and Figure ).…”

Section: Results and Discussionmentioning

confidence: 99%

“…Hence, it is greatly desired to broaden the Δ T of NTE and simultaneously retain large α L . Recently, Hu et al reported that the temperature range of MT would be effectively broadened by introducing the residual strain (RS) in Mn-basehexagonal systems. , In this work, therefore, the RS is introduced into the fine-powdered Mn 0.965 Co 1.035 Ge prepared via high energy BM. The MT temperature interval, and accordingly Δ T , is significantly broadened, while the very large α L is retained simultaneously.…”

Section: Introductionmentioning

confidence: 99%

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Controllable Negative Thermal Expansion by Mechanical Pulverizing in Hexagonal Mn_0.965Co_1.035Ge Compounds

Yang

Liu

et al. 2018

Inorg. Chem.

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Negative thermal expansion (NTE) material as a compensator is very important for accurately controlling the thermal expansion of materials. Along with the magnitude of the coefficient of thermal expansion, the operating temperature window of the NTE materials is also a major concern. However, only a few of the NTE materials possess both a large operating temperature range and a large thermal expansion coefficient. To explore this type of new NTE material, the Mn 0.965 Co 1.035 Ge fine powders were prepared by mechanical ball milling (BM). These fine powders show a largely extended NTE operation temperature window simultaneously possessing a giant thermal expansion coefficient. For samples treated with different BM times, such as the BM-0.5h, BM-4h, and BM-12 h samples, the operating temperature window (ΔT) and linear thermal expansion coefficient (α L ) are 167 K (222−389 K) and ∼ −63 ppm/K, 221 K (140−360 K) and ∼ −41.3 ppm/K, and 208 K (234−442 K) and ∼ −40 ppm/K, respectively, which are larger than most wellknown NTE materials. More strikingly, all BM samples have a large constant linear NTE coefficient with an ultrawide temperature window covering room temperature. For these three samples, these values are ∼ −52 ppm/K (140 K), ∼ −58.3 ppm/K (110 K), and ∼ −65 ppm/K (80 K), respectively. The origin of the excellent NTE properties is discussed based on the thermomagnetic measurements and X-ray absorption spectroscopic results.

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Stress modulated martensitic transition and magnetocaloric effect in hexagonal Ni2In-type MnCoGe1−xInx alloys

Cited by 27 publications

References 31 publications

Critical dependence of magnetostructural coupling and magnetocaloric effect on particle size in Mn-Fe-Ni-Ge compounds

Critical dependence of magnetostructural coupling and magnetocaloric effect on particle size in Mn-Fe-Ni-Ge compounds

Negative Thermal Expansion in the Materials With Giant Magnetocaloric Effect

Controllable Negative Thermal Expansion by Mechanical Pulverizing in Hexagonal Mn_0.965Co_1.035Ge Compounds

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Stress modulated martensitic transition and magnetocaloric effect in hexagonal Ni2In-type MnCoGe1−xInx alloys

Cited by 27 publications

References 31 publications

Critical dependence of magnetostructural coupling and magnetocaloric effect on particle size in Mn-Fe-Ni-Ge compounds

Critical dependence of magnetostructural coupling and magnetocaloric effect on particle size in Mn-Fe-Ni-Ge compounds

Negative Thermal Expansion in the Materials With Giant Magnetocaloric Effect

Controllable Negative Thermal Expansion by Mechanical Pulverizing in Hexagonal Mn0.965Co1.035Ge Compounds

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Product

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Controllable Negative Thermal Expansion by Mechanical Pulverizing in Hexagonal Mn_0.965Co_1.035Ge Compounds