Presentation in the ISMANAM'11 conference held in Gijon (Spain)

1. Introduction Results Conclusions
Enhancing the working temperature span and refrigerant
capacity of two-phase composite systems based on
amorphous FeZrBCu ribbons
P. Alvarez1 J.L. Sánchez-Llamazares2 P. Gorria1 J.A. Blanco1
1 University of Oviedo, Spain
2 Instituto Potosino de Investigación Científica y Tecnológica, Mexico
International Symposium on Metastable, Amorphous and Nanostructured
Materials

2. Introduction Results Conclusions
Outline
1 Introduction
Magnetocaloric Effect
Improving the Relative Cooling Power
2 Results
Magnetocaloric Properties
Combined System
3 Conclusions

3. Introduction Results Conclusions
Magnetocaloric Effect
The Magnetic Entropy Change and the Relative Cooling Power
Temperature dependence of
Magnetization for GdAl2 and its
relation with the MCE
Maxwell Relation
Isothermal Magnetic Entropy Change
H2 ∂M
∆S (T , H2 )P,∆H = dH
H1 ∂T P,H

4. Introduction Results Conclusions
Magnetocaloric Effect
The Magnetic Entropy Change and the Relative Cooling Power
Temperature dependence of Relative Cooling Power (RCP)
Magnetization for GdAl2 and its
relation with the MCE
Estimation of RCP
Peak
Maxwell Relation RCP1 (H) = |∆SM (H) | × δTFWHM
TH
Isothermal Magnetic Entropy Change RCP2 (H) = |∆SM (T , H)| dT .
TC
H2 ∂M
∆S (T , H2 )P,∆H = dH RCP3 (H) = max ∆Smag (T1 , H) × (T2 − T1 )
H1 ∂T P,H

5. Introduction Results Conclusions
Improving the Relative Cooling Power
Composite Compounds: an Effective way to Improve the RCP via the ∆SM (T ) Broadening
Past: Low Temperature
Magnetic Composites
T. Hashimoto et al., J. Appl. Phys. 62 (9)
(1987) 3873-3878

6. Introduction Results Conclusions
Improving the Relative Cooling Power
Composite Compounds: an Effective way to Improve the RCP via the ∆SM (T ) Broadening
Past: Low Temperature Recent: RCP Improvement around RT by
Magnetic Composites Using Magnetic Composites
T. Hashimoto et al., J. Appl. Phys. 62 (9)
(1987) 3873-3878 R. Caballero-Flores et al., Appl. Phys. Lett. 98 (2011) 102505

7. Introduction Results Conclusions
Improving the Relative Cooling Power
Composite Compounds: an Effective way to Improve the RCP via the ∆SM (T ) Broadening
Past: Low Temperature Recent: RCP Improvement around RT by
Magnetic Composites Using Magnetic Composites
T. Hashimoto et al., J. Appl. Phys. 62 (9)
(1987) 3873-3878 R. Caballero-Flores et al., Appl. Phys. Lett. 98 (2011) 102505
Further Comments
RCP Optimization for a Two-Phase
Magnetic Composite The Maximum Refrigeration Efficiency is
attained with Constant Magnetic Entropy
Shape of ∆SM (T ) Change curves.
δTC
A.M. Tishin and Y.I. Spichkin. Magnetocaloric Effect
Weight Fraction of Both Phases and Its Applications. Series in Condensed Matter
Physics, 1 edition (2003).
Applied Magnetic Field

8. Introduction Results Conclusions
FeZrBCu amorphous alloys
Nanoperm Alloys
∆SM (T ) for Nanoperm alloys
P. Alvarez et al., Intermetallics 18 (2010)
2464-2467

9. Introduction Results Conclusions
FeZrBCu amorphous alloys
Nanoperm Alloys
∆SM (T ) for Nanoperm alloys
P. Alvarez et al., Intermetallics 18 (2010)
2464-2467
FeZrBCu Amorphous Alloys Produced
Fe90 Zr10 - Fe90 Zr9 B1 - Fe91 Zr7 B2 - Fe90 Zr8 B2
Fe88 Zr8 B4 - Fe86 Zr7 B6 Cu1 - Fe87 Zr6 B6 Cu1
Arc-melting Bulk alloy → Melt-spinning → Amorphous Ribbons

10. Introduction Results Conclusions
Advantages
Advantages of FeZrBCu alloys for their use in Two-Phase Composite Systems
Advantages
Easy to produce (Melt
spinning technique)
Low Cost (Fe-Based
alloys)
Large MS values
Second Order Magnetic
Phase Transition
Tunable TC in a wide range
Broad ∆SM (T ) curves

11. Introduction Results Conclusions
Advantages
Advantages of FeZrBCu alloys for their use in Two-Phase Composite Systems
Advantages Magnetization Isotherms
Easy to produce (Melt
spinning technique)
Low Cost (Fe-Based
alloys)
Large MS values
Second Order Magnetic
Phase Transition
Tunable TC in a wide range MS ≈ 125 − 135 emu g−1
Broad ∆SM (T ) curves

12. Introduction Results Conclusions
Advantages
Advantages of FeZrBCu alloys for their use in Two-Phase Composite Systems
Advantages Magnetization Isotherms
Easy to produce (Melt
spinning technique)
Low Cost (Fe-Based
alloys)
Large MS values
Second Order Magnetic
Phase Transition
Tunable TC in a wide range MS ≈ 125 − 135 emu g−1
Broad ∆SM (T ) curves
Typical Arrott Plot

13. Introduction Results Conclusions
Advantages
Advantages of FeZrBCu alloys for their use in Two-Phase Composite Systems
Advantages Magnetization Isotherms
Easy to produce (Melt
spinning technique)
Low Cost (Fe-Based
alloys)
Large MS values
Second Order Magnetic
Phase Transition
Tunable TC in a wide range MS ≈ 125 − 135 emu g−1
Broad ∆SM (T ) curves
TC vs Fe Content
Typical Arrott Plot

14. Introduction Results Conclusions
Advantages
Advantages of FeZrBCu alloys for their use in Two-Phase Composite Systems
Advantages Magnetization Isotherms
Easy to produce (Melt
spinning technique)
Low Cost (Fe-Based
alloys)
Large MS values
Second Order Magnetic
Phase Transition
Tunable TC in a wide range MS ≈ 125 − 135 emu g−1
Broad ∆SM (T ) curves
TC vs Fe Content
Typical Arrott Plot

15. Introduction Results Conclusions
Magnetocaloric Properties
Magnetic Entropy Change
A general view to ∆SM (T ) curves
for amorphous FeZrCuB alloys

16. Introduction Results Conclusions
Magnetocaloric Properties
Magnetic Entropy Change
A general view to ∆SM (T ) curves
for amorphous FeZrCuB alloys

17. Introduction Results Conclusions
Magnetocaloric Properties
Typical RCP and δTFWHM values of amorphous FeZrCuB alloys
RCP-1
Metallic Gd
RCP1(µ0 H = 5 T) = 687 Jkg−1
RCP2(µ0 H = 5 T) = 503 Jkg−1
RCP-2

18. Introduction Results Conclusions
Magnetocaloric Properties
Typical RCP and δTFWHM values of amorphous FeZrCuB alloys
RCP-1
Metallic Gd
RCP1(µ0 H = 5 T) = 687 Jkg−1
RCP2(µ0 H = 5 T) = 503 Jkg−1
Width of the ∆SM (T ) Curves
RCP-2

19. Introduction Results Conclusions
Combined System
A Concrete Two-Phase Composite based on amorphous FeZrCuB ribbons: EXAMPLE 1
∆SM (T ) curves of Component
A (Fe90 Zr9 B1 ) and B (Fe87 Zr6 B6 Cu1 )

20. Introduction Results Conclusions
Combined System
A Concrete Two-Phase Composite based on amorphous FeZrCuB ribbons: EXAMPLE 1
∆SM (T ) curves of Component ∆SM (T ) curves of the Composite System
A (Fe90 Zr9 B1 ) and B (Fe87 Zr6 B6 Cu1 ) 0.4 A + 0.6 B

21. Introduction Results Conclusions
Combined System
A Concrete Two-Phase Composite based on amorphous FeZrCuB ribbons: EXAMPLE 2
∆SM (T ) for the two-ribbon system
0.5 A (Fe87 Zr6 B6 Cu1 ) + 0.5 B (Fe90 Zr8 B2 )

22. Introduction Results Conclusions
Combined System
A Concrete Two-Phase Composite based on amorphous FeZrCuB ribbons: EXAMPLE 2
Increase of δTFWHM for the Two-Phase System
0.5 A (Fe87 Zr6 B6 Cu1 ) + 0.5 B (Fe90 Zr8 B2 )
∆SM (T ) for the two-ribbon system
0.5 A (Fe87 Zr6 B6 Cu1 ) + 0.5 B (Fe90 Zr8 B2 )

23. Introduction Results Conclusions
Combined System
A Concrete Two-Phase Composite based on amorphous FeZrCuB ribbons: EXAMPLE 2
Increase of δTFWHM for the Two-Phase System
0.5 A (Fe87 Zr6 B6 Cu1 ) + 0.5 B (Fe90 Zr8 B2 )
∆SM (T ) for the two-ribbon system
0.5 A (Fe87 Zr6 B6 Cu1 ) + 0.5 B (Fe90 Zr8 B2 )
Resulting RCP for the Two-Phase System
0.5 A (Fe87 Zr6 B6 Cu1 ) + 0.5 B (Fe90 Zr8 B2 )
RCP ≈ 95% of Metallic Gd

24. Introduction Results Conclusions
Combined System
Flattening of the ∆SM (T ) Curve
Flattening of ∆SM (T ) for the system
0.5 A (Fe87 Zr6 B6 Cu1 ) + 0.5 B (Fe90 Zr8 B2 )

25. Introduction Results Conclusions
Combined System
Flattening of the ∆SM (T ) Curve
Flattening of ∆SM (T ) for the system
0.5 A (Fe87 Zr6 B6 Cu1 ) + 0.5 B (Fe90 Zr8 B2 )

26. Introduction Results Conclusions
Conclusions
In this contribution we experimentally show that a combination
of two Nanoperm amorphous ribbons forming a two-phase
composite system may lead to:
A considerably increase of the δTFWHM with the consequent
enhancement in the RCP;
A Flattening of the ∆SM (T ) curve which improves the
refrigerant efficiency of the refrigerant thermodynamic cycle.
The latter is possible due to the broad ∆SM (T ) curve shown by
Nanoperm alloys and their combination in a proper way (i.e, the
right selection of both, the δTC of the two alloys chosen to form
the composite, and the relative weight fraction).

27. Introduction Results Conclusions
Conclusions
In this contribution we experimentally show that a combination
of two Nanoperm amorphous ribbons forming a two-phase
composite system may lead to:
A considerably increase of the δTFWHM with the consequent
enhancement in the RCP;
A Flattening of the ∆SM (T ) curve which improves the
refrigerant efficiency of the refrigerant thermodynamic cycle.
The latter is possible due to the broad ∆SM (T ) curve shown by
Nanoperm alloys and their combination in a proper way (i.e, the
right selection of both, the δTC of the two alloys chosen to form
the composite, and the relative weight fraction).
THANKS FOR YOUR ATTENTION!