Transcript Glass formability, thermal stability and mechanical

2009 IEEE Magnetic Society Summer School
Investigation on magnetocaloric effect of La0.8Ce0.2Fe11.4-xNixSi1.6 compounds
Zhiping Lin, Shandong Li*, Meimei Liu, Jianglin Fang, and Jenq-Gong Duh
Department of Physics, Fujian Normal University, Fuzhou 350007, P.R.China
◆Abstract
The effect of Ni doping into Magnetocaloric effect (MCE) material La0.8Ce0.2(FeSi)13 has been studied. It is interesting to find that
Curie temperature (Tc) of La0.8Ce0.2(FeSi)13 compounds can be adjusted by the substitution of Ni for Fe. With the increase of Ni
content, a reduction of thermal lag and magnetic hysterisis was observed, while working temperature span improved obviously.
-1
-1
La0.8Ce0.2Fe10.9Ni0.5Si1.6 remains a larger MCE value of 6J.Kg .K and an enhancement over 20 K at Tc under 3T. The compounds
exhibit a magnetic transition from first-order to second-order.
140
120
185K
190K
200K
100
LaFeSi
a-Fe
178K
100
80
208K
215K
225K
80
60
Intensity(a.u)
(b)
185K
187K
x=0.5
60
250K
40
40
x=0.4
20
x=0.3
0
190K
0
0
10000
16000
x=0.1
30
40
x=0.0
50
60
70
30000
0
10000
(c)
80
2degree
Fig. 1 X-ray diffraction patterns of the annealed
La0.8Ce0.2Fe11.4-xNixSi1.6 (x=0, 0.1, 0.2, 0.3, 0.4, 0.5)
165K
(d)
185K
12000
10000
10000
8000
8000
6000
6000
250K
4000
2000
2000
0
0
0
140 150 160 170 180 190 200 210 220 230 240
Temperature(K)
Fig. 2 The thermomagnetic M-T curves for La0.8Ce0.2Fe11.4(x=0, 0.1, 0.2, 0.3, 0.4,0.5)compounds under 0.1 T
300
400
500
600
700
H/M(Oe.g/emu)
Fig. 3 M-H curve for (a) La0.8Ce0.2Fe11.4Si1.6 (b) La0.8Ce0.2Fe11Ni0.5Si1.6
And Arrott plots for (c) La0.8Ce0.2Fe11.4Si1.6 and (d) La0.8Ce0.2Fe11Ni0.5Si1.6
7
80
(a)
(b)
6
70
5
50
40
1T
30
2T
20
3T
-S(J/Kg.K)
-S(J/Kg.K)
10
200
H/M(Oe.g/emu)
x=0.0
x=0.1
x=0.2
x=0.3
x=0.4
x=0.5
20
4000
200K
60
xNixSi1.6
14000
12000
50
30
30000
Applied field(Oe)
100 200 300 400 500 600 700 800 900 100
40
20000
14000
M2(emu/g) 2
20
20000
Applied field(Oe)
x=0.2
T/ T
T
l
g
lg x m
x
m
20
Magnetization(emu/g)
120
1:13 phase
Magnetization(emu/g)
170K
175K
M2(emu/g) 2
◆Result and discussion
(a)
2
1
0
0
175
180
185
Temperature(K)
190
2T
3T
3
10
170
1T
4
135 150 165 180 195 210 225 240
Temperature(K)
Fig. 4 The magnetic entropy change plot for La0.8Ce0.2Fe11.4-xNixSi1.6
(a)x=0.0, (b) x=0.5 under 1, 2, 3T applied field
◆Conclusions
The compounds of La0.8Ce0.2Fe11.4-xNixSi1.6(x=0, 0.1, 0.2, 0.3, 0.4, 0.5) hold a large maximum △S and amplificatory
temperature span, which suggests a great refrigeration capacity. Ni addition induce an enhancement of Tc in NaZn13-type
compounds as reported in Co doping, and dramatical reduction in thermal lag and hysteresis loss. In conclusion, the
substitution of Ni for La0.8Ce0.2Fe11.4-xNixSi1.6 (x=0, 0.1, 0.2, 0.3, 0.4, 0.5) exihibits a fantastic application preview in magnetic
refregaration, and possibly adjust the working temperature to room temperature.
◆Acknowledgements
Supported by NCET-08-0631, NSFC (10504010 and 50501008), and 2009H0019.
*Corresponding author: Prof. Shandong Li, Tel:86+0591-28198956 Email: [email protected]