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Hybrid High-Temperature Nanostructured Magnets

Published online by Cambridge University Press:  21 March 2011

David J. Sellmyer ,
J. Zhou ,
H. Tang  and
R. Skomski
David J. Sellmyer
Affiliation:
Behlen Laboratory of Physics and Center for Materials Research and AnalysisUniversity of NebraskaLincoln, NE 68588-0113, USA
J. Zhou
Affiliation:
Behlen Laboratory of Physics and Center for Materials Research and AnalysisUniversity of NebraskaLincoln, NE 68588-0113, USA
H. Tang
Affiliation:
Behlen Laboratory of Physics and Center for Materials Research and AnalysisUniversity of NebraskaLincoln, NE 68588-0113, USA
R. Skomski
Affiliation:
Behlen Laboratory of Physics and Center for Materials Research and AnalysisUniversity of NebraskaLincoln, NE 68588-0113, USA
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Abstract

The hysteretic behavior of two-phase permanent magnets for high-temperature applications is examined. A variety of systems have been synthesized and investigated, including Sm-Co-Cu-Ti bulk magnets, SmCo5:Cu-Ti thin-film materials, and mechanically milled Sm-CoZr magnets. The hybrid character of the material leads to very high room-temperature coercivities, between 30.2 and 43.6 kOe, and to the survival of a comparatively large part of the coercivity at high temperatures (12.3 kOe at 500 °C for SmCo 6.5Cu0.8Ti0.3). The coercivity reflects the structure and chemical composition of the material. When ferromagnetic grains are separated by a ferromagnetic boundary phase, the boundary phase acts as a pinning center, but when the grain-boundary phase has a comparatively low Curie temperature, the high-temperature magnetism of the system is that of a weakly interacting ensemble of magnetic particles. In spite of some residual paramagnetic exchange coupling, which is discussed in this work, this mechanism enhances the coercivity.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 674: Symposia T/U/V – Applications of Ferromagnetic and Optical Materials, Storage and Magnetoelectronics , 2001 , U5.8
Copyright
Copyright © Materials Research Society 2001

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References

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