L. Maosa, A. Planes, E. Vives M.Barrio, J.L. Tamarit D. Gonzlez, E. - - PowerPoint PPT Presentation

Lluís Mañosa. Departament ECM. Facultat de Física. Universitat de Barcelona. lluis@ecm.ub.es

• D. Soto Parra

CIMAV, Chihuahua Mexico.

• R. Romero

IFIMAT, Tandil. Argentina

• I. Titov, M. Acet
• Univ. Duisburg

Germany.

• L. Mañosa, A. Planes, E. Vives
• D. González, E. Stern
• Univ. Barcelona.

Catalonia. M.Barrio, J.L. Tamarit

• Univ. Polit. Catalunya.

Catalonia.

• A. Battacharyya, S. Majumdar

Indian Assoc. Cultivation Science Kolkata, India.

• X. Moya, N. Mathur
• Univ. Cambridge

U.K.

Modern society relies on the possibility of cooling below ambient

q1 q2

Cold sink Hot sink

K

How to cool ?

Rudolf Emmanuel Clausius (1822-1888) Henri Poincaré (1854-1912)

q1 q2

Cold sink Hot sink

K

NOT FOR FREE !!!!

Work

How to cool ?

The simplest cycle: The Carnot Cycle

T S R   

Need: Materials with large changes in entropy and temperature

S T

|q1|= T1S T = T2 –T1 |q2|= T2S

Refrigerant capacity

Undergraduate Thermodynamics

Caloric effects

Large caloric effects when is large

Generalized displacement Generalized field

Y

ΔSiso = Sf – Si < 0 Tf = Ti

S(T,Y=0) S(T,Y)

S T

Siso



 

                  

Y T adi Y T iso

dY Y S C T ΔT dY Y S ΔS

Isothermal entropy change

Y

ΔTadi = Tf – Ti < 0 Sf = Si

S(T,Y=0) S(T,Y)

S 

Tadi

 

                  

Y T adi Y T iso

dY Y S C T ΔT dY Y S ΔS

Adiabatic temperature change

 In general  Siso<0 when Y > 0 T x

H

         Sample heats up when applying field adiabatically  Conventional caloric effect But..... T x

H

          Siso > 0 when Y > 0  Sample cools down when applying field adiabatically Inverse caloric effect

Caloric effect

T

S

ΔSiso < 0 ΔTad > 0 S(H=0) S(H≠0) MCE

T

S

ΔSiso < 0 ΔTad > 0 S(Y=0) ≠0) ΔSiso > 0 ΔTad < 0 S(Y≠0) Inverse CE S(Y=0) S(Y≠0)

Computation of caloric effects From Maxwell relation: Isothermal measurements x vs Y Calorimetric (adiabatic, relaxational, ac,..) measurement of C under field Direct methods: adiabatic measurement of temperature Other methods: pulsed fields, Clausius-Clapeyron, etc…

Undergraduate Thermodynamics

Caloric effects

Large caloric effects when is large

Generalized displacement Generalized field

Measurements of entropy changes at a first order phase transition:

DSC Calorimetry under constant temperature (T): sweeping field ( Y ) DSC Calorimetry under constant field ( Y ): sweeping temperature (T)

S dQ/dY Y

285 290 295 300 305 200 400 600 800

dQ/dT (mW/K) T(K)

T0 T

dQ/dT T

• S (J K
• 1 kg
• 1)

T (K)

• S (J K
• 1 kg
• 1)

T (K)

T

Pt-100 thermometer Sample Thermobatteries Hall probe

1 Cu block 2 Sensors (thermobatteries) 3 Sample 4 Reference 5 Carbon-glass resistor (T) 16 mm

Marcos et al., Rev. Sci.Ints., 74, 4768 (2003)

Calorimeters under magnetic field.

Cells O-ring Capillary

Screw

Metallic O-ring

E

Cu BaTiO3

Calorimeter under hydrostatic pressure. Calorimeters under electric field.

Barocaloric effect: Ni-Mn-In, La-Fe-Co-Si

• L. Mañosa et al. Nature Mater. 9 (2010) 478.
• L. Mañosa et al. Nature Comm. 2(2011) 595.

Magneto caloric effect: Ni-Mn-Sn; Ni-Mn-In

• T. Krenke et al. Nature Mater. 4 (2005) 450

A FEW EXPERIMENTAL RESULTS Elastocaloric effect: Cu-Zn-Al

• E. Bonnot et al. Phys. Rev. Lett. 100 (2008) 125901.

Electrocaloric effect: BaTiO3

Magnetic shape memory alloys

Martensitic transition

(a) (b)

Heusler X2YZ Change in symmetry + Change in magnetization + Change in volume + Change in strain (Fm3m)

Magnetocaloric effect is inverse: entropy increases on applying field Ni-Mn-Sn

Magnetocaloric effect

Ni-Mn-X (X=Sn,In,Sb,Ga)

• T. Krenke et al. Nature Mater. 4 (2005) 450

Magnetocaloric effect

• T. Krenke et al. Nature Mater. 4 (2005) 450
• L. Mañosa et al., Adv. Mater. 21 (2009) 3725.

Ni-Mn-X (X=Sn,In,Sb,Ga)

Magnetocaloric effect

• X. Moya et al. Phys. Rev. B 75 (2007) 184412

Ni-Mn-X (X=Sn,In,Sb,Ga)

Ni-Mn-In

Inverse magnetocaloric: Sample cools on applying Magnetic field.

• L. Mañosa et al Nature Mater. 9 (2010) 478

Ni-Mn-In

Barocaloric effect

• L. Mañosa et al Nature Mater. 9 (2010) 478

Ni-Mn-In

Barocaloric effect

CONVENTIONAL INVERSE

La-Fe-Si

No change in symmetry + Change in magnetization + Change in volume NaZn13 structure (Fm-3c)

• L. Mañosa et al Nature Commun. 2 (2011) 595

Barocaloric effect Magnetocaloric effect

• L. Mañosa et al Nature Commun. 2 (2011) 595

Barocaloric effect Magnetocaloric effect

INVERSE CONVENTIONAL

• L. Mañosa et al Nature Commun. 2 (2011) 595

Inverse caloric effect Sample warms up

• n releasing pressure.

Conventional caloric effect Sample cools down

• n removing field.

Shape memory alloys (the classic ones)

Martensitic transition

(a) (b)

Heusler X2YZ Change in symmetry + NO Change in volume + Change in strain (Fm3m)

Elastocaloric effect

Cu0.6813Zn0.1574Al0.1613

 

T

S S d d T

  

                        

 

• E. Bonnot et al.
• Phys. Rev. Lett 100 (2008) 125901

296 298 300 302 304 306 308 310 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

=105MPa =110MPa =115MPa =120MPa =125MPa =130MPa =135MPa =140MPa =143MPa

• S (J/K.mol)

T (K)

molK J dT dT dQ T S

f s

M M

/ 3 . 1 1    



Ms Mf

molK J dT d V S

t t

/ 2 . 1       

ΔSmax=ΔSt = -1.2 J/mol K = - 20 J/kg K calorimetry Clausius-Clapeyron

Elastocaloric effect

• E. Vives et al. Appl. Phys. Lett. 98 (2011) 011902

Adiabatic temperature change

Elastocaloric effect

BaTiO3

Change in symmetry + Change in volume + Change in polarization Pm3m P4/mmm

394 396 398 400 2 E = 3 kV cm

• 1

S (J K

• 1 kg
• 1)

T (K)

E = 0 kV cm

• 1

T - C phase transition (cooling)

E

Cu BaTiO3

394 396 398 400

• 2000
• 1000

E = 0 kV cm

• 1

E = 3 kV cm

• 1

dQ/dT (J K

• 1 kg
• 1)

T (K)

394 396 398 400 1 2 E = 2 kV cm

• 1

E = 3 kV cm

• 1
• S (J K
• 1 kg
• 1)

T (K)

Electrocaloric effect

Sweeping temperature

394 396 398 400 1 2 E = 4 kV cm

• 1
• S (J K
• 1 kg
• 1)

T (K)

Field-induced transition

E

Cu BaTiO3

100 200 300 400 500

• 0.0010
• 0.0008
• 0.0006
• 0.0004
• 0.0002

0.0000 calorimetric signal Electric Field (kV/m)

T= 397.28 K

Electrocaloric effect

Sweeping electric field

Indirect method: P(T,E)

380 400 420 10 20 E = 0 kV cm

• 1

E = 4 kV cm

• 1

P (C cm

• 2)

T (K)

• 20
• 10

10 20

• 20
• 10

10 20 385 K 405 K

P (C cm

• 2)

E (kV cm

• 1)

P(E) different T (cooling) P(T) different E ECE

380 400 420 2 E = 4 kV cm

• 1
• S (J K
• 1 kg
• 1)

T (K)

Electrocaloric effect

394 396 398 400 1 2 3 E = 4 kV cm

• 1

E sweep E = 3 kV cm

• 1
• S (J K
• 1 kg
• 1)

T (K)

T sweep 380 400 420 2 E = 4 kV cm

• 1
• S (J K
• 1 kg
• 1)

T (K)

Direct Indirect

Electrocaloric effect

395 400 405 410 415 420 0.5 1.0 100 200

• 1.0
• 0.5

0.5 1.0 100 200 Eon Eoff

T (K)

T (K) E = 8 kV cm

• 1

Eoff

T (K) t (s) 404 K

Eon

409 K t (s)

Eon Eoff

Electrocaloric effect

T S T X Y  Y= 0 S T |St| |St| T S T S T X Y= 0  Y |St| |St|

CONVENTIONAL CALORIC EFFECT INVERSE CALORIC EFFECT

ΔS = ΔSmag +ΔSstr +ΔSel

S low T < S high T

Low entropy phase

Entropy increases S > 0 Entropy decreases S < 0 Low (high) magnetization High (low) magnetization

High entropy phase Caloric effect latent heat of the transition

Low volume Low strain Large volume Large strain Field applied Pressure released Stress released Field removed Pressure applied Stress applied

Materials with structural transitions + LARGE changes in extensive properties (Cross-response to external stimuli) GIANT caloric effects Eco-friendly refrigeration Energy Harvesting

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