19-11-2010

Challenge the future

DelftUniversity ofTechnology

Magnetocaloric materials for Room-temperature applicationsEkkes Brück, Fundamental Aspects of Materials and Energy, TNW

2Magnetocaloric materials

Refrigeration

15% world energy consumption

Strong greenhouse gases

3Magnetocaloric materials

Magnetic refrigeration:

External magnetic field changes temperature of magnetic material

No CFCs, permanent magnets, easy scalable, high efficiency, low noise

Important parameters!

ΔT temperature change

ΔS entropy change

4Magnetocaloric materials

spins lattice

Basic magnetocalorics

E

Two energy reservoirs

5Magnetocaloric materials

E

Basic magnetocalorics

spins lattice

6Magnetocaloric materials

Develop energy-efficient refrigerator, operated in field of permanent magnet.

→ modern magnets ≤ 2.5 tesla

→ refrigerator regenerator design

→ Layered beds to increase T span

→ cycle frequency (power)

→ efficient heat-exchangers

7Magnetocaloric materials

2001 Model magnetic refrigerator

C. Zimm, Astronautics Co.

8Magnetocaloric materials

1.5T

9Magnetocaloric materials

Chubu and Toshiba Refrigerator 2003

(Gd, Dy) metal

Rotating magnet

0.76 T

Cooling power

60 W

T span 20 K

10Magnetocaloric materials

11Magnetocaloric materials

Okamura 2005, 2007

560 W @ 1.1T

12Magnetocaloric materials

Magnetocaloric airconditioner

Sari et al 2007

13Magnetocaloric materials

Tura & Rowe 2009

14Magnetocaloric materials

T (C0)

T (C

0 )

Increased T span with layered bed containing different materials with tailored Tc

15Magnetocaloric materials

Multimaterial regenerator

Rowe & Tura Int.J.Ref. 2006

16Magnetocaloric materials

Gd foil0.8 (P)48.8reciprocatingApril 2003Grenoble, FranceLab. d’Electrontechnique

Grenoble

Gd1-xDyx layered bed0.76 (P)1060rotaryMar. 4, 2003Yokohama, JapanChubu Electric/Toshiba

Gd1-xDyx layered bed0.6 (P)2740reciprocatingOct. 5, 2002Yokohama, JapanChubu Electric/Toshiba

Gd spheres; Gd5(Si,Ge)4 pwdr.b1.4 (P)23?reciprocatingMarch 4, 2003Nanjing, ChinaSichuan Inst. Tech./

Nanjing University

Gd spheres1.5 (P)2095rotarySept. 18, 2001Madison, Wisconsin, USAAstronautics

Gd & Gd1-xTbx layered bed2 (S)142reciprocatingJuly 2001Victoria, British Columbia

Canada

University of Victoria

Gd spheres4 (S)21100reciprocatingSummer 2000Yokohama, JapanChubu Electric/Toshiba

Gd foil0.95 (P)5?rotaryMay 2000Barcelona, SpainMater. Science Institute

Barcelona

Gd spheres5 (S)10600reciprocatingFeb. 20, 1997Madison, Wisconsin, USAAmes Laboratory/ Astronautics

Regenerator

Material

Magnetic Fielda

µ0H(T)

Max.

T

(K)

Cooling

Power

(W)

TypeAnnouncement

Date

LocationName

aMagnetic field source: S = superconducting magnet; P = permanent magnetbActual composition Gd5(Si1.985Ge1.985Ga0.03)

Room-temperature magnetic refrigerators

17Magnetocaloric materials

11 prototypes 2009

Frequ. Power ΔT magn. mater.

18Magnetocaloric materials

Giant MCE materials

1990 FeRh (Nikitin et al.)1997 Gd5Si2Ge2 (Percharsky & Gschneidner Jr.)1998 RCo2 (Foldeaki et al. )2000-2002 La(Fe,Si)13 (Hu et al., Fukamichi et al.) 2001 MnAs1-xSbx (Wada et al.)2002 MnFe(P,As) (Tegus et al.)2003 Co (S1-xSex)2 (Yamada & Goto)2005 NiMnSn (Krenke et al.)2009 MnCoGeB (Trung et al.)

19Magnetocaloric materials

0 1 2 3 4 50.0

0.5

1.0

1.5

2.0

2.5

M (

B/f.u

.)

B (T)

at 310 K

MnFeP0.46As0.54

For example

Magnetization processes

Materials with field induced first order phase transition.

20Magnetocaloric materials

La(Fe,Si)13 compounds

Cubic CaZn13 type of structure stabilized by addition of 10% Si(Kripyakewich et al. 1968)Invar type of behavior and unusual magnetic transition(Palstra et al 1983)Difficult to obtain single phase.

Gutfleisch et al 2004Meltspun almost single phase

21Magnetocaloric materials

Concentration dependence of Curie temperature and moment

Palstra et al. 1983

Tc increase with dilution

22Magnetocaloric materials

LaFe13 system

APL Zhang et al 2000Fujieda et al 2002

MCE decrease with dilution

23Magnetocaloric materials

PRB Fujita et al 2003

Tc increase with hydrogen!

Sharp transition maintained!

LaFe13 system with hydrogen

24Magnetocaloric materials

260 280 300 320 3400

5

10

15

20

-S

(J/k

g K

)

T (K)

Gd metal LaFe11.4Si1.6H

LaFe11.4Si1.6H1.5 LaFe11.4Co0.5Si1.1 LaFe11.2Co0.7Si1.1

0-2T

Fujita et al Phys Rev B 67 (2003) Hu, et al, JAP 97 (2005)

25Magnetocaloric materials

Field driven 1st order metamagnetictransition around 200 K .

La(Fe,Si)13 cubic above magnetic transition

cubic below

volume change 1.5%. Low Tc can be increased by addition of Cobalt or Hydrogen.

Hysteretic transition: stability of hydrogenation?mechanical stability?

Summary La(Fe,Si)13

26Magnetocaloric materials

MnFeP1-xAsx

Hexagonal Fe2P type of structure

Bacmann, JMMM 1994

Space group:

P62m

Mn 3g sites

Fe 3f sites

P/As 1b&2c sites

_

27Magnetocaloric materials

Sample preparation

Starting Fe2P, Mn2As3, Mn & P

mechanical alloying

sintering 1000oC

annealing 800oC

28Magnetocaloric materials

Magnetization process near Tc

Field induced transition with small hysteresis

29Magnetocaloric materials

Temperature dependence of Magnetization

Step-liketransition

first order

but very littlehysteresis

30Magnetocaloric materials

Comparison of magnetocaloric effect in different materials

Entropy changeconcentrated inrelevant T interval Tegus et al. Nature 415

31Magnetocaloric materials

285 290 295 300 305 310 3150

1

2

3

4

5B = 1.45 T

MnFeP0.45As0.55MnFeP0.47As0.53

Mn1.1Fe0.9P0.47As0.53

T ad

(K)

T (K)

Direct measurements MSU

Adiabatic temperature-change

Sample dependence need for careful preparation

32Magnetocaloric materials

For active magnetic regenerator

0 1 2 3 cm

MnFePAs sintered

Extrudedgreen

Shaping of materials

33Magnetocaloric materials

200 220 240 260 280 300 3200

10

20

30

40

50

60

70

M (A

m2 /k

g)

T (K)

1

2

3

Mn1.1Fe0.9P0.78Ge0.22

0.1 T

Virgin effect and large hysteresis

Arsenic has bad reputation in kitchen

Sample with Ge replacing As

34Magnetocaloric materials

Sample with Ge replacing As

Melt-spinning

+ Ar gas pressure 1 atm.

surface speed of the wheel v = 40m/s+

ribbons were annealed for ± 10 min.+

Mn2-xFexP0.75Ge0.25 (x = 0.70, 0.76, 0.78, 0.80)+

35Magnetocaloric materials

Small thermal hyteresis, Tc = 288 K

Large MCE observed at low operation field

Sample with Ge replacing As

36Magnetocaloric materials

Challenges with Fe2P materials

As bad reputationGe expensiveSi or Al could be perfect

37Magnetocaloric materials

MnFe(P,Si) first samples

Large hysteresis

50 100 150 200 250 3000

10

20

30

40

50

M(A

m2 /k

g)

T(K)

1st cooling heating 2ndcooling

B = 50 mTsweep rate 2K/min

MnFeP0.6Si0.4

38Magnetocaloric materials

Toxic ingredients0.1 %Hex. – hex.150-340250-580

MnFe(P,As)(P, Ge, Si)

Fe corrosion sensitiveH uptake

1.5 %Cubic -cubic

200-330La(Fe,Si)13Hy

High purity Gdrequired

hysteresis

0.5 %Ortho. –monokl.

130-270Gd5Ge2+xSi2-x

CommentsVStruct.Tc

(K)Alloy

Comparison giant magneto-caloric materials

39Magnetocaloric materials

Availability

60t?WW prod=90t, avail 10t

?GaNi0.501Mn0.227Ga0.258

4000

4000

unlimited

WW prod=90t, avail 10t

?

1000

Estimated

availability

7000tLaManganites

LaMnO3

22000tLaLathanum alloys

La(Fe13-xMx)

No limitation for an

industrial productionnone

Manganese alloys

Mn(As1-xSbx)

MnFe(P1-xSix)

140tGeGadolinium Silicon alloys

Gd4(Si1-xGex)5

1000tGdGd metal

Total availability of

MC material

Limiting

ingredient

40Magnetocaloric materials

Classical Technology:

Temperature range < 200 °C not considered

Magnetocaloric Technology: 75% of Carnot Efficiency

High Temperature (600 °C)Permanent magnets XMC-materials X

Low temperature (<200 °C)Permanent magnets ✔MC-materials ✔Access to waste heat

Heat- to electric-power conversion

41Magnetocaloric materials

dBTMTdTcTdSdQ p

Heat input → temperature changemagnetization change

2222

dtdB

RSNRIWelect

42Magnetocaloric materials

Magnetocaloric power generation

43Magnetocaloric materials

Stack of materials in generator

44Magnetocaloric materials

Various machine concepts were developed in the past.Lack of suited magneto-caloric materials prohibited realization of these.The novel materials showing giant-magneto-caloric effects near and above RT can lead to realization.

Summary MC power generation

45Magnetocaloric materials

People involved in project in Delft

• Senior scientists: Jürgen Buschow, Niels van Dijk• Pos docs: Lian Zhang, Luana Caron, Cam Thanh Dinh• PhD students: Thanh Trung Nguyen, Zhiqiang Ou, Huu Dung

Nguyen, Jose Leitao• Technician: Anton Lefering

46Magnetocaloric materials

Thank you

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