Iowa State University Patents Iowa State University Research Foundation, Inc.

7-8-2003

Method of making active magnetic refrigerant,colossal magnetostriction and giantmagnetoresistive materials based on Gd-Si-GealloysKarl A. Gschneidner Jr.Iowa State University, cagey@ameslab.gov

Alexandra O. PecharskyIowa State University

Vitalij K. PecharskyIowa State University, vitkp@ameslab.gov

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Recommended CitationGschneidner, Karl A. Jr.; Pecharsky, Alexandra O.; and Pecharsky, Vitalij K., "Method of making active magnetic refrigerant, colossalmagnetostriction and giant magnetoresistive materials based on Gd-Si-Ge alloys" (2003). Iowa State University Patents. 289.http://lib.dr.iastate.edu/patents/289

Method of making active magnetic refrigerant, colossal magnetostrictionand giant magnetoresistive materials based on Gd-Si-Ge alloys

AbstractMethod of making an active magnetic refrigerant represented by Gd5(SixGe1−x)4alloy for 0≦x≦1.0 comprisingplacing amounts of the commercially pure Gd, Si,and Ge charge components in a crucible, heating the chargecontents under subambient pressure to a melting temperature of the alloy for a time sufficient to homogenizethe alloy and oxidize carbon with oxygen present in the Gd charge component to reduce carbon, rapidlysolidifying the alloy in the crucible, and heat treating the solidified alloy at a temperature below the meltingtemperature for a time effective to homogenize a microstructure of the solidified material, and then coolingsufficiently fast to prevent the eutectoid decomposition and improve magnetocaloric and/or themagnetostrictive and/or the magnetoresistive properties thereof.

KeywordsAmes Laboratory, Materials Science and Engineering

DisciplinesEngineering Physics | Metallurgy

This patent is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/patents/289

United States Patent US006589366B1

(12) (10) Patent N0.: US 6,589,366 B1 Gschneidner, Jr. et al. (45) Date of Patent: Jul. 8, 2003

(54) METHOD OF MAKING ACTIVE MAGNETIC OTHER PUBLICATIONS

REFRIGERANT’ COLOSSAL E.M. Levin, V.K. Pecharsky, and K.A. Gschneidner, Jr., MAGNETOSTRICTION AND GIANT “Magnetic ?eld and temperature dependencies of the elec MAGNETORESISTIVE MATERIALS BASED trical resistance near the magnetic crystallographic ?rst 0N GD'SI'GE ALLOYS order phase transition of Gd5 (Si2Ge2)”, Phys. Rev. B60,

_ . 7993—7997 (1999).

(75) Inventors‘ 1%‘; l_éAlGsch5leld3eIi’) Jrl'l’ Anlies’ A12 V.K. Pecharsky and K.A. Gschneidner, Jr., “Phase relation ( )’ exen ,lja ' ec ars y’ es’ ships and Crystallography in the Pseudobinary System IA (US)' V1tali] K Pecharsky Ames - IA Us ’ ' ’ ’ Gd5S14—Gd5Ge4”, J. Alloys Compds. 260, 98—106 (1997).

( ) V.K. Pecharsky and K.A. Gschneidner, Jr., “Tunable Mag . _ . . netic Regenerator Alloyss With a Giant Magnetocaloric

(73) Asslgnee' iiztvlillgszgenUlnlizelzlgesRisAezzlgg) Effect for Magnetic Refrigeration from ~20 to~290K”, Appl. ’ " ’ Phys. Lett. 70, 3299—3301 (1997).

( * ) Notice: Subject to any disclaimer, the term of this V'K' pecharsky a.nd K'A' G.S"hne1§ner’ Jr" “Glam Magne patent is extended or adjusted under 35 tocalor1c Effect in Gd5 (S12Ge2) , Phys. Rev. Lett. 78, U.S.C. 154(b) by 0 days. 44944497 (1997)

V.K. Pecharsky and K.A. Gschneidner, Jr., “Effect of Alloy _ ing on the Giant Magnetocaloric Effect of Gd5 (Si2Ge2)”, J.

(21) APPL NO" 09/793,822 Magn. Magn. Mater. 167, L179—L184(1997). (22) Filed? Feb- 23! 2001 (List continued on neXt page.)

Related US Application Data Primary Examiner—John Sheehan (60) Provisional application No. 60/187,713, ?led on Mar. 8, (57) ABSTRACT

2000. 7 _ _ Method of making an active magnetic refrigerant repre

(51) Int. Cl. ....................... .. H01F 1/053, F25R 21/00, Sented by Gd5(SixGe1_x)4 alloy for 05x5“) Comprising F2513 9/00 placing amounts of the commercially pure Gd, Si, and Ge

(52) US. Cl. ..................... .. 148/301; 148/101; 148/103; Charge Components in a Crucible, heating the Charge Contents _ 148/121; 62/31; 62/6 under subambient pressure to a melting temperature of the

Fleld Of Search ............................... .. alloy for a time Su?icient to homogenize the alloy and 148/103, 301, 303, 120, 121, 122; 62/31, oXidiZe carbon With oXygen present in the Gd charge com

4, 6, 51-1 ponent to reduce carbon, rapidly solidifying the alloy in the _ crucible, and heat treating the solidi?ed alloy at a tempera

(56) References Clted ture beloW the melting temperature for a time effective to

Us. PATENT DOCUMENTS homogeniZe a microstructure of the solidi?ed material, and then cooling suf?ciently fast to prevent the eutectoid decom position and improve magnetocaloric and/or the magneto strictive and/or the magnetoresistive properties thereof.

36 Claims, 25 Drawing Sheets

5,743,095 A * 4/1998 Gschneidner et al. ....... .. 62/3.1

6,022,486 A * 2/2000 Tokai et al. ................ .. 252/67

6,030,468 A * 2/2000 Yagi et al. ...... .. 148/301 6,336,978 B1 * 1/2002 Tokaiet al. .............. .. 148/301

18 l l l

-o— H=0-1T

16

14 ~

12

if, 10 X

5 m5 8 4i

0 240 250 260 270 280 290

W‘) 300 310 320

US 6,589,366 B1 Page 2

OTHER PUBLICATIONS

T.B. Massalski, Editor—in—Chief, Binary Alloy Phase Dia grams, 2”“ ed., ASM International, Materials Park, Ohio (1990). D.H. Dennison, M.J. Tschetter and K.A. Gschneidner, Jr., “The Solubility of Tantalurn in Eight Liquid Rare—Earth Metals”, J. Less—Cornrnon Metals 10, 109—115 (1965). P. Rogl, “Phase Equilibria in Ternary and Higher Order Systems With Rare Earth Elements and Silicon” in Hand book on the Physics and Chemistry of Rare Earths, K.A. Gschneidner, Jr. and L. Eyring, eds., Elsevier Science Pub lishers, B.V., Amsterdam, pp. 92—94 (1984). L. Morellon, P.A. Algarabel, M.R. Ibarra, J. Blasco, and B. Garcia—Landa, “Magnetic—?eld—induced structural phase transition in Gd5 (Si1_8Ge2_2)”, Phys. Rev. B58, 721—724 (1998).

L. Morellon, J. StankieWicZ, B. Garcia—Landa, P.A. Alga rabel, and MR. Ibarra, “Giant rnagnetoresistance near the rnagnetostructural transition in Gd5 (Si1_8Ge2_2)”, Appl. Phys. Lett. 73, 3462—3464 (1998). L. Morellon, J. Blasco, P.A. Algarabel, and MR. Ibarra, “Nature of the ?rst—order antiferrornagnetic—ferrornagnetic transition in the Ge—rich rnagnetocaloric cornpounds Gd5 (SixGe1_x)4”, Phys. Rev. B62, 1022—1026 (2000). J. StankieWicZ, L. Morellon, P.A. Algarabel, and MR. Ibarra, “Hall effect in Gd5 (Si1_8Ge2_2)”, Phys. Rev. B61, 12651—12653 (2000). L. Morellon, P.A. Algarabel, C. Magen, and MR. Ibarra, “Giant rnagnetoresistance in the Ge—rich rnagnetocaloric cornpound, Gd5 (SiO_1GeO_9)4”, J. Magn. Magn. Mater. 237, 119—123 (2001).

* cited by eXarniner

U.S. Patent Jul. 8,2003 Sheet 2 0f 25 US 6,589,366 B1

; + H=0-1T _

s _- —B— H=0-2T L

-ASm(J/kg K)

250 260 270 280 290 300 310 320

T(K)

U.S. Patent Jul. 8,2003 Sheet 3 0f 25 US 6,589,366 B1

U.S. Patent Jul. 8,2003 Sheet 5 0f 25 US 6,589,366 B1

320 300 280

T(K) 260

12

240

2 9.52m?

Fig. 5

U.S. Patent

-ASm(JIkg K)

Jul. 8, 2003 Sh??t 6 0f 25 US 6,589,366 B1

-——v——H=O-4T 8——§—H=O-5T —

6

4..

2_

O lllllllllllllll'llllllllllllllllllllll

240 250 260 270 280 290 300 310 320

Fig. 6

W0

U.S. Patent Jul. 8,2003 Sheet 10 0f 25 US 6,589,366 B1

-ASm(Jlkg K)

T(K)

Fig. 10

U.S. Patent Jul. 8,2003 Sheet 11 0f 25 US 6,589,366 B1

320

|

300 280

W‘)

l

260 240

2 9:252

Fig. 11

U.S. Patent

-ASm(Jlkg K)

12

10

Jul. 8,2003 Sheet 12 0f 25 US 6,589,366 B1

——E—— H=0-2T

+ H=0-3T

f ——v— H=O-4T L + H=0-5T

I If F I r

Jjllllllll llllllllll llllllllllllll

250 260

Fig. 12

270 280 290 300 310

T(K) 320

U.S. Patent Jul. 8,2003 Sheet 13 0f 25 US 6,589,366 B1

12 . - I I . ' »

- ——0— H=0-1T

' —E!— H=0-2T

: —+— H=0-3T 10 ~ + H=O-4T v

F + H=0-5T

-ASm(Jlkg K) CD

0 1 1 l u I | | 1 | l | l 1 | l l

240 260 280 300 320

Fig. 13

U.S. Patent Jul. 8,2003 Sheet 14 0f 25 US 6,589,366 B1

35

20 -ASm(Jlkg K) 15

101

O | |

240

T(K)

Fig. 14

U.S. Patent Jul. 8,2003 Sheet 15 0f 25 US 6,589,366 B1

From heat capacity measurements

—o-— As-prepared alloy + Enhanced MCE

350 300 250 150 200

T (K)

100 50

U.S. Patent Jul. 8,2003 Sheet 16 0f 25 US 6,589,366 B1

18 J """ “I """" "1 ' ' 1 ' ' ' ' "l 111111 "I """" "I """" "I ' I ' ' ' ' ' "I ' ' ' ' ' ' ' "I """" “I 1 ' I I ' 1‘ _

f Direct measurements §

16

14 j- _

12

2 1° 2 "r, E

I- 1 4 8 .- —

6 -

4 Gd5(S|2Ge2) 5 Field change 0-5T

2 ;“ —O—— As-prepared alloy '3 _ + Enhanced MCE :

O ...... ..| ....... ..| ....... ..| ....... ..| ....... 1,1 1111111 “l ....... ..| ....... ..1 ....... Ml ....... .E

250 255 260 265 270 275 280 285 290 295 300

T(K) Fig. 15b

U.S. Patent Jul. 8,2003 Sheet 17 0f 25 US 6,589,366 B1

40 _' ‘ ' ' ' ’ ‘ "I ‘ ' ' ‘ 1 ' ' "I ‘ ' ' ' ' ‘ ' "I ' ' ' 1 ' ‘ ' “I ' ' ' ‘ ‘ ' ' "I ' ‘ ' ' ' ' ' l‘I ' ‘ ‘ ' ' ' ‘ "I ' ‘ ‘ ' ' ‘ ‘ l'I ' ' ' 1 ' ‘ ' I‘I ' ' ' ' ‘ " _

From magnetization measurements E

35 Gd5(S|2Ge2) __ E Field change 0-5T§ I —O— As-prepared alloyi

30 :- —-A=— Enhanced MCE ‘;

25 E E2 : U7 :

é : 3 20 - E I w <,1 :

15 I

10 f

5f

0 I '

250 255 260 265 270 275 280 285 290 295 300

T (K) Fig. 150