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Calorimetric Studies of the A1 to L1 0 transformation in FeNiPt thin films Velouse Pierre Advisor: Katayun Barmak Mentors: David Berry.

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Presentation on theme: "Calorimetric Studies of the A1 to L1 0 transformation in FeNiPt thin films Velouse Pierre Advisor: Katayun Barmak Mentors: David Berry."— Presentation transcript:

1 Calorimetric Studies of the A1 to L1 0 transformation in FeNiPt thin films Velouse Pierre Advisor: Katayun Barmak Mentors: David Berry

2 Fe-Pt Binary Phase Diagram A1 L1 0

3 DSC Traces and Kissinger Plot Fe 49.1 Ni 2.7 Pt 48.2 Φ (˚C/min) Tpeak (˚C) Fe:Ni:Pt 50.3 : 7.8 : : 2.7 : : 1.6 : : 6.3 : : 16.9 : 50.0

4 Curie Temperature

5 Kinetic Ordering Temperature

6 Effects of Composition on Properties

7 Lattice Parameters

8 Summary of Thermodynamic and Kinetic Parameters EDXRF Fe : Ni :Pt Tpeak (°C) Tcurie ordered (°C) Tcurie disordered (°C) Q (eV) ΔH (kJ/g- atom) Avrami Exponent, n Woldt Michaelsen- Dahms 50.3 : 7.8 : ± ± ± ± ± : 2.7 : ± ± ± ± : 1.6 : ± ± ± ± : 6.3 : ± ± ± ± ± : 16.9 : ―291.7 ± ± ± ± 0.1

9 Summary and Conclusions Keeping iron content constant and replacing platinum with nickel in the ternary alloy, the Curie temperature increases. Higher nickel content increases ordering temperature. Higher iron content results in a lower activation energy, thus resulting in faster ordering kinetics. Transformation enthalpy is lower with higher nickel content which causes it to have a lower driving force. Avrami exponent being low shows that transformation needs higher temperatures to be completed.

10 Acknowledgements This work was supported by MRSEC and PREM research of National Science Foundation. Great appreciation goes to Carnegie Mellon University and its staff. The highest thanks also goes to Dr. Katayun Barmak, David Berry, and Jihwan Kim for all their help and support.


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