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Search for magnetism in Co and Fe-doped HfO2 thin films for potential spintronic applications

Published online by Cambridge University Press:  01 February 2011

M. S. R. Rao
Affiliation:
Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742
Darshan C. Kundaliya
Affiliation:
Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742
S. Dhar
Affiliation:
Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742
C. A. Cardoso
Affiliation:
Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742
A. Curtin
Affiliation:
Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742
S. J. Welz
Affiliation:
Department of Chemical Engineering and Materials Science, University of California at Davis, California 95616 and
R. Erni
Affiliation:
Department of Chemical Engineering and Materials Science, University of California at Davis, California 95616 and
N. D. Browning
Affiliation:
Lawrence Berkeley National Laboratory, NCEM, One Cyclotron Road, Berkeley, California 94720
S. E. Lofland
Affiliation:
Department of Chemistry and Physics, Rowan University, Glassboro, New Jersey 08028–1701
C. J. Metting
Affiliation:
Department of Chemistry and Physics, Rowan University, Glassboro, New Jersey 08028–1701
S. B. Ogale
Affiliation:
Department of Materials Science, University of Maryland, College Park, Maryland 20742
T. Venkatesan
Affiliation:
Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, MD 20742, USA and
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Extract

We studied the structural and magnetic properties of dilutely (5 mol%) doped 3d elements (Co and Fe) in PLD grown HfO2 high-k dielectric thin films. Monoclinic phase of HfO2 was stabilized by Co- and Fe- substitution at significantly low growth temperature (∼725 °C). No magnetic moment was observed in Co-doped HfO2 films. On the other hand, 5 mol% Fe-doped HfO2 films grown at different oxygen partial pressures (10-6 torr to 10 mtorr) showed interesting magnetization behavior with varying coercive field due to the segregation of Fe2O3 and Fe3O4 phases. Magnetic force microscopy (MFM) study revealed magnetic impurity phase segregation. Films grown at 1 × 10-4 torr of oxygen partial pressure (O2pp) showed oriented Fe3O4 impurity line (220) and the coercive field (Hc) ∼ 350 Oe. Films grown at higher oxygen partial pressure (1x10-2 torr) showed no impurities and magnetization was absent. Coercive field varied as a function of oxygen partial pressure. This property will be of great interest from the view point of magneto-optic applications.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

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References

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