Magnetocaloric and Magnetic Properties of Meta‐Magnetic Heusler Alloy Ni41Co9Mn31.5Ga18.5

Sakon, Takuo; Kitaoka, Takuya; Tanaka, Kazuki; Nakagawa, Hiroyuki Nojiri Keisuke; Adachi, Yasuhiro; Kanomata, T.

doi:10.5772/64375

Cited by 4 publications

(8 citation statements)

References 55 publications

(51 reference statements)

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“…This unconventional phenomenon is called the inverse magnetocaloric effect (IMCE). The IMCEs were also observed in other compositions Ni 50 Mn 50Àx Z x (Z = Ga, In, Sn and Sb) [13][14][15][16][19][20][21][22][23]. The IMCE indicates the significant positive change in entropy through the MFIMT that exceeds the negative contribution from the spin ordering.…”

Section: Mces In Ni-mn-based Heusler Alloysmentioning

confidence: 66%

“…In addition, the direct measurement of MCE is also important because it enables us to evaluate the magnetic part of entropy as presented in Section 4. However, numerous studies have attempted to understand the IMCE in these materials through indirect methods such as magnetization and/or specific heat, which can only reveal the total entropy change [13][14][15][16][17][19][20][21][22][23].…”

Section: Mces In Ni-mn-based Heusler Alloysmentioning

confidence: 99%

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Magnetocaloric Effects in Metamagnetic Shape Memory Alloys

Kihara¹,

Xu²,

Ito³

et al. 2017

Shape Memory Alloys - Fundamentals and Applications

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Recently, metamagnetic shape memory alloys have attracted much attention as candidates for the rare-earth free magnetic refrigerants. These materials undergo the martensitic transformation (MT) at around room temperature accompanied by a significant entropy change. The application of the magnetic field at the low-temperature martensitic phase realizes the magnetic field-induced martensitic transformation (MFIMT). Through the MFIMT, the materials show an unconventional magnetocaloric effect (MCE), which is called inverse magnetocaloric effect (IMCE). In this chapter, the direct measurement system of MCE in pulsed-high-magnetic fields is introduced. With taking the advantage of the fast field-sweep rate of pulsed field, adiabatic measurements of MCE are carried out at various temperatures. Using this technique, the IMCEs of the metamagnetic shape memory alloys NiCoMnIn and NiCoMnGa are directly measured as adiabatic temperature changes in pulsed fields. From the experimental data of MCE for NiCoMnIn, the entropy of spin system in the austenite phase is estimated through a simple mean-field model. By the combination of MCE, magnetization and specific heat measurements, the electronic, lattice and magnetic contributions to the IMCE are individually evaluated. The result for NiCoMnIn demonstrates that lattice entropy plays the dominant role for IMCE in this material.

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Section: Mces In Ni-mn-based Heusler Alloysmentioning

confidence: 66%

Section: Mces In Ni-mn-based Heusler Alloysmentioning

confidence: 99%

Magnetocaloric Effects in Metamagnetic Shape Memory Alloys

Kihara¹,

Xu²,

Ito³

et al. 2017

Shape Memory Alloys - Fundamentals and Applications

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“…In the former article, we studied the magneto-caloric properties of Ni 41 Co 9 Mn 31.5 Ga 18.5 polycrystalline sample by means of the differential scanning calorimetry (DSC) measurements [25].…”

Section: Relation Between the Magnetic Field-induced Strain And The Mmentioning

confidence: 99%

“…Figure 3 shows the temperature dependence of the MFIS and entropy change. The entropy change ΔS = S(6 T) -S(0 T) was obtained from magnetization results and DSC results between zero field and 6 T, from the DSC results ΔS in steady fields [25].…”

Section: Relation Between the Magnetic Field-induced Strain And The Mmentioning

confidence: 99%

“…In our former article [25], we determined the magnetic field dependence of the magnetization of Ni 41 Co 9 Mn 31.5 Ga 18.5 around the Curie temperature in the martensite phase in order to investigate the properties of the itinerant electron magnetism according to Takahashi's spin fluctuation theory of itinerant electron magnetism [26,27]. The M 4 versus H/M plot was crossed across the coordinate axis at the Curie temperature in the martensite phase, T CM = 263 K, and indicates a good linear relation behavior around T CM .…”

Section: Introductionmentioning

confidence: 98%

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Magnetic Field-Induced Strain of Metamagnetic Heusler Alloy Ni41Co9Mn31.5Ga18.5

Sakon¹,

Fujimoto²,

Saruki³

et al. 2018

Shape-Memory Materials

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Ni 41 Co 9 Mn 31.5 Ga 18.5 is a re-entrant and metamagnetic Heusler alloy. In order to investigate the magnetic functionality of polycrystalline Ni 41 Co 9 Mn 31.5 Ga 18.5 , magnetic field-induced strain (MFIS) measurements were performed. A 0.12% MFIS was observed at 340 K and 10 T. Strict MFISs between 330 and 370 K were observed. These magneto-structural variances acted in concert with the metamagnetic property observed by the magnetization measurements and magneto-caloric property observed by the caloric measurements in applied magnetic fields. The MFISs were proportional to the fourth power of the magnetization, and this result is in agreement with Takahashi's spin fluctuation theory of itinerant electron magnetism. The investigation of time response of the MFIS was performed by means of water-cooled electric magnet, zero magnetic field to 1.66 T in 8.0 s at 354 K. A 2.2×10 −4 MFIS was observed, which was 80% of the MFIS in a 60-s mode. This indicates that a high-speed transition has occurred on applying magnetic fields.

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Observation of inverse magnetocaloric effect in magnetic-field-induced austenite phase of Heusler alloys Ni50−xCoxMn31.5Ga18.5

Kihara

Roy

et al. 2021

Phys. Rev. Materials

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measurements were performed in both pulsed and steady high magnetic fields to investigate the magnetocaloric properties of Heusler alloys Ni50-xCoxMn31.5Ga18.5 (x = 9 and 9.7). From direct MCE measurements for Ni41Co9Mn31.5Ga18.5 up to 56 T, a steep temperature drop was observed for magnetic-field-induced martensitic transformation (MFIMT), designated as inverse MCE.Remarkably, this inverse MCE is apparent not only with MFIMT, but also in the magnetic-fieldinduced austenite phase. Specific heat measurements under steady high magnetic fields revealed that the magnetic field variation of the electronic entropy plays a dominant role in the unconventional magnetocaloric properties of these materials. First-principles based calculations performed for Ni41Co9Mn31.5Ga18.5 and Ni45Co5Mn36.7In13.3 revealed that the magnetic-field-induced austenite phase of Ni41Co9Mn31.5Ga18.5 is more unstable than that of Ni45Co5Mn36.7In13.3 and that it is sensitive to slight tetragonal distortion. We conclude that the inverse MCE in the magnetic-field-induced austenite phase is realized by marked change in the electronic entropy through tetragonal distortion induced by the externally applied magnetic field.

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Magnetocaloric and Magnetic Properties of Meta‐Magnetic Heusler Alloy Ni41Co9Mn31.5Ga18.5

Cited by 4 publications

References 55 publications

Magnetocaloric Effects in Metamagnetic Shape Memory Alloys

Magnetocaloric Effects in Metamagnetic Shape Memory Alloys

Magnetic Field-Induced Strain of Metamagnetic Heusler Alloy Ni41Co9Mn31.5Ga18.5

Observation of inverse magnetocaloric effect in magnetic-field-induced austenite phase of Heusler alloys Ni50−xCoxMn31.5Ga18.5

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