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Thermodynamic Evaluation of the Interface Stability Between Selected Metal Oxides and Co

Published online by Cambridge University Press:  03 March 2011

Ying Yang*
Affiliation:
Materials Science and Engineering Department, University of Wisconsin, Madison, Wisconsin 53706
Peter F. Ladwig
Affiliation:
Materials Science Program, University of Wisconsin, Madison, Wisconsin, 53706
Y. Austin Chang
Affiliation:
Materials Science and Engineering Department and Materials Science Program, University of Wisconsin, Madison, Wisconsin 53706
Feng Liu
Affiliation:
Recording Head Operations, Seagate Technology, Bloomington, Minnesota 55435
Bharat. B. Pant
Affiliation:
Recording Head Operations, Seagate Technology, Bloomington, Minnesota 55435
Allan E. Schultz
Affiliation:
Recording Head Operations, Seagate Technology, Bloomington, Minnesota 55435
*
a)Address all correspondence to this author. e-mail:yaying@cae.wisc.edu
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Abstract

For an interface to be considered thermodynamically stable, the phases in contact must be in equilibrium with each other (connected by a stable tie-line) and have negligible mutual solubility on the phase diagram. The stability of Co based magnetic tunnel junctions (MTJs), with Co/MxO1-x/Co structures (M = Al, Gd, Hf, La, Mg, Si, Ti, Ta, Y and Zr), were evaluated with regard to these two conditions. Specifically, low temperature ternary isothermal phase diagrams were calculated and evaluated for the Co–M–O systems. All of these systems have at least one oxide in equilibrium with Co and thus have at least one thermodynamically stable tunnel barrier candidate for use in Co based MTJs. In light of the assumptions made in this analysis, along with the uncertainty in applying bulk enthalpy data to thin films, the current evaluation of interfacial stability serves as a first step in identifying suitable stable tunneling barrier materials in MTJs for detailed study.

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Articles
Copyright
Copyright © Materials Research Society 2004

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References

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