Magnetic properties of nanocrystalline {gamma}{prime}-Fe{sub 4}N and {var_epsilon}-Fe{sub 3}N synthesized by citrate route

Journal Article · Sun Mar 01 04:00:00 EST 1998 · IEEE Transactions on Magnetics

DOI:https://doi.org/10.1109/20.661488· OSTI ID:616188

Panda, R N; Gajbhiye, N S ^[1]

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1. Indian Inst. of Tech., Kanpur (India). Dept. of Chemistry

Nanocrystalline {gamma}{prime}-Fe{sub 4}N and {var_epsilon}-Fe{sub 3}N nitrides are synthesized by using a citrate precursor route. The nitridation of {alpha}-Fe{sub 2}O{sub 3} results in a nitrogen deficient perovskite {gamma}{prime}-Fe{sub 4}N phase at 773 K and hexagonal {var_epsilon}-Fe{sub 3}N phase at 823 K. The nitride particle is a magnetic cluster consisting of an assembly of crystallites. {gamma}{prime}-Fe{sub 4}N is a weak itinerant ferromagnet and the particles exhibit acicular platelet-like morphology. The magnetic moments in ultrafine {gamma}{prime}-Fe{sub 4}N and {var_epsilon}-Fe{sub 3}N nitride particles are due to spin pairing effects, lattice expansion due to interstitial nitrogens, superparamagnetic behavior, and randomly canted spin structures at the surface. The reduction of magnetization and Curie temperature (T{sub c}) is attributed to fine particle size effects. In {gamma}-Fe{sub 4}N and {var_epsilon}-Fe{sub 3}N, the intermixing of N-2p states with Fe-3d states occurs because of similarities in their density of states, and thus the reduction of unpaired d-electrons results in the lowering of magnetic moments compared to {alpha}-Fe. The Mossbauer study of {gamma}{prime}-Fe{sub 4}N and {var_epsilon}-Fe{sub 3}N nitrides indicate randomly canted spin structures at the surface and corroborates the observed magnetic properties.

• OSTI ID: 616188
• Journal Information: IEEE Transactions on Magnetics, Journal Name: IEEE Transactions on Magnetics Journal Issue: 2Pt2 Vol. 34; ISSN IEMGAQ; ISSN 0018-9464
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CURIE POINT
FERROMAGNETISM
GRAIN SIZE
IRON NITRIDES
MAGNETIC PROPERTIES
MORPHOLOGY
PRECURSOR
SYNTHESIS