Magnetocaloric effect and magnetic field-inducedmartensitic transformation in metamagnetic shape

memory alloys

Pablo Alvarez-Alonso

C.O. Aguilar-Ortiz, J. López-García, J.P. Camarillo, D. Salazar, P. Lazpita,H. Flores-Zuñiga, and V.A. Cherneko

Energy Materials NanotechnologySan Sebastián (2015)

Introduction Measurement of ∆Tad Results Conclusions

Collaboration

BCMaterials and University of the Basque Country

JavierLópez-García

Dr. Daniel SalazarJaramillo

Dr. PatriciaLazpita

Dr. VolodymyrChernenko

Instituto Potosino de Investigación Científica y Tecnológica (Mexico)

Juan PabloCamarillo

Christian O.Aguilar-Ortiz

Dr. HoracioFlores-Zuñiga

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Outline

1 Introduction

2 Direct measurement of Adiabatic Temperature Change

3 ResultsNi-Mn-In bulk alloysNi-Mn-Sn Ribbons

4 Conclusions

Introduction Measurement of ∆Tad Results Conclusions

Shape Memory Alloys

Shape Memory Alloys

Martensitic Transformation (First-order)Difussionless phase transition by nucleation

Austenite: CubicMartensite: Low symmetry

Variants↓

Equivalent crystal structures with differentorientations

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Introduction Measurement of ∆Tad Results Conclusions

Metamagnetic shape memory alloys

Metamagnetic Shape Memory Alloys

Ni-Mn-X Heusler alloys(X = In, Sn, Sb, . . . )

↓Field-induced reverse MT

↓Metamagnetic Shape Memory Effect −→

R. Kainuma et al. Nature 439 (2006) 957-960

A. Planes et al. J. Phys.: Condens. Matter. 21 (2009) 2332012 / 17

Introduction Measurement of ∆Tad Results Conclusions

Magnetocaloric Effect

Magnetocaloric Effect

Total Entropy

Magnetic refrigeration

O. Tegus et al. Nature 415 (2002) 150-152

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Introduction Measurement of ∆Tad Results Conclusions

Magnetocaloric Effect

Magnetic Entropy Change

M (T ) and its relation with ∆SM (T )

P. Alvarez-Alonso et al., Phys. Rev. B. 86(2012)184411

Isothermal Magnetic Entropy Change

Maxwell Relation

∆S (T , H) = −∫ H

0

(∂M∂T

)P,H

dH

Refrigerant capacity

P. Gorria et al., J. Phys. D: Appl. Phys. 41 (2008)192003

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Introduction Measurement of ∆Tad Results Conclusions

Magnetocaloric Effect

Adiabatic Temperature Change

Temperature dependence of ∆Tad for Gd Indirect measurement

∆Tad (T , H) = −∫ Hmax

0

TCP,H

(∂M∂T

)P,H

dH

P. Alvarez-Alonso et al. Key Eng. Mater. 644 (2015) 215-218

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Introduction Measurement of ∆Tad Results Conclusions

Measurement system

P. Alvarez-Alonso et al. Key Eng. Mater. 644 (2015) 215-218

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-In bulk alloys

Martensitic Transformation

Ni50Mn35In15

Ni50Mn32Cr2In16

Ni47.5Cu2.5Mn35In15

+Heat treatment (900 ◦C - 1 day )

Specimen Composition MS MF AS AF |∆H|

(at. %) (K) (K) (K) (K) (J/g)

Ni50Mn35 In15 Ni50.1Mn35.3In14.6 303 289 304 316 8.8

Ni50Mn32Cr2In16 Ni49.9Mn32.9Cr2.5In14.7 294 277 290 304 10.7

Ni47.5Cu2.5Mn35In15 Ni48.4Cu2.9Mn35.0In13.7 268 259 272 282 6.9

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-In bulk alloys

Magnetization measurements: Low Magnetic Field

Moderate thermal hysteresis (≈ 12 K )

Specimen T MC (K ) T A

C (K )

Ni50Mn35In15 203 314

Ni50Mn32Cr2In16 214 297

Ni47.5Cu2.5Mn35In15 193 305

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-In bulk alloys

Magnetization measurements: High Magnetic Field

TM = (MS + MF ) /2, TA = (AS + AF ) /2

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-In bulk alloys

MCE: Adiabatic Temperature Change

Martensitic Transformation Magnetic Phase Transition

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-Sn Ribbons

Martensitic Transformation

Ni50-xFexMn40Sn10

(x = 0, 2, 4, 6, 8)

NO Heat treatment

Specimen Composition MS MF AS AF |∆H|

(at. %) (K) (K) (K) (K) (J/g)

Ni50Mn40Sn10 Ni50.3Mn39.7Sn9.9 425 408 423 438 16.5

Ni48Fe2Mn40Sn10 Ni48.5Fe2.2Mn39.5Sn9.8 375 358 377 386 14.4

Ni46Fe4Mn40Sn10 Ni46.6Fe4.0Mn39.4Sn9.9 356 340 356 367 14.0

Ni44Fe6Mn40Sn10 Ni45.2Fe6.3Mn38.6Sn9.9 310 297 309 322 13.2

Ni42Fe8Mn40Sn10 Ni42.6Fe8.1Mn39.6Sn9.7 285 267 286 299 12.9

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-Sn Ribbons

Crystal Estructure and Microstructure

a) Ni50Mn40Sn10 b) Ni48Fe2Mn40Sn10

Austenite: B2

Martensite: 6M-orthorhombic

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-Sn Ribbons

Crystal Structure

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-Sn Ribbons

Magnetization measurements: Low Magnetic Field

Low thermal hysteresis (≈8 K )

Specimen T MC (K ) T A

C (K )

Ni50Mn40Sn10 185 444

Ni48Fe2Mn40Sn10 176 393

Ni46Fe4Mn40Sn10 174 369

Ni44Fe6Mn40Sn10 181 322

Ni42Fe8Mn40Sn10 171 287

T0 = (TM + TA)/2

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-Sn Ribbons

Magnetization measurements: High Magnetic Field

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Introduction Measurement of ∆Tad Results Conclusions

Ni-Mn-Sn Ribbons

MCE: Magnetic Entropy Change

Inverse MCE

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Introduction Measurement of ∆Tad Results Conclusions

Conclusions

Influence of doping elements (Fe, Cr, and Cu) and magnetic field onthe MT and MCE in Ni50Mn35In15 and Ni50Mn40Sn10 metamagneticshape memory alloys.

Small dopping by Cu (Cr) instead Ni (Mn) reduces the critical MTtemperatures of the Ni-Mn-In bulk. Ni substitution by Fe linearlydecreases T A

C and MT temperatures for Ni-Mn-Sn ribbons.

The magnetic field decreases the MT temperatures (up to 40 Kfor 12 T ).

∆SmaxM ≈11 J/kgK under µ0∆H =5 T ; ∆Tad up to −2.7 K for

µ0∆H =1.9 T .

Compositional variation of the MSMA by a small doping is effectiveway to tune the parameters responsible for the MCE in thesematerials.

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