Magnetic exchange hardening in polycrystalline GdN thin films

Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK.
Journal of Physics Condensed Matter (Impact Factor: 2.35). 08/2010; 22(30):302003. DOI: 10.1088/0953-8984/22/30/302003
Source: PubMed


We report the observation of intrinsic exchange hardening in polycrystalline GdN
thin films grown at room temperature by magnetron sputtering. We find,
in addition to the ferromagnetic phase, that a fraction of GdN crystallizes in a
structural polymorphic form which orders antiferromagnetically. The relative
fraction of these two phases was controlled by varying the relative abundance of
reactive species in the sputtering plasma by means of the sputtering power and
N2 partial pressure. An
exchange bias of ~ 30?Oe was observed at 10?K. The exchange coupling between the ferromagnetic and the
antiferromagnetic phases resulted in an order of magnitude enhancement in the coercive
field in these films.

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