Magnetic properties of nanocrystalline ε-Fe{sub 3}N and Co{sub 4}N phases synthesized by newer precursor route

Journal Article · Fri Nov 15 04:00:00 EST 2013 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2013.07.043· OSTI ID:22285180

Theerthagiri, J.; Dalavi, Shankar B. ^[1]; Manivel Raja, M. ^[2]

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1. Department of Chemistry, Birla Institute of Technology and Science, Pilani, K.K. Birla, Goa Campus, Zuari Nagar, Goa 403726 (India)
2. Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)

Graphical abstract: Nanocrystalline ε-Fe{sub 3}N and Co{sub 4}N nitride phases are synthesized first time by newer chemical routes. The ε-Fe{sub 3}N phase crystallizes in hexagonal structure with unit cell parameters, a = 4.76 Å and c = 4.41 Å. The Co{sub 4}N phase crystallizes in face centred cubic (fcc) structure with unit cell parameters, a = 3.55 Å. The estimated crystallite size for ε-Fe{sub 3}N and Co{sub 4}N phases are 29 nm and 22 nm, respectively. The values of saturation magnetization for ε-Fe{sub 3}N and Co{sub 4}N phases are found to be 28.1 emu/g and 123.6 emu/g respectively. The reduction of magnetic moments in ultrafine materials compared to bulk materials has been explained by fine particle size and surface effects. We have synthesized the high moment ε-Fe{sub 3}N and Co{sub 4}N nitride with reduced coercivity which may find applications as soft magnetic materials. - Highlights: • Nanocrystalline ε-Fe{sub 3}N and Co{sub 4}N nitride phases are synthesized. • The ε-Fe{sub 3}N and Co{sub 4}N crystallizes in hexagonal and fcc structure respectively. • The observed magnetic parameters indicate soft magnetic properties. • The magnetic properties have been explained on the basis of fine particle magnetism. - Abstract: Nanocrystalline ε-Fe{sub 3}N and Co{sub 4}N nitride phases are synthesized first time by using tris(1,2-diaminoethane)iron(II) chloride and tris(1,2-diaminoethane)cobalt(III) chloride precursors, respectively. To prepare ε-Fe{sub 3}N and Co{sub 4}N nitride phases, the synthesized precursors were mixed with urea in 1:12 ratio and heat treated at various temperatures in the range of 450–900 °C under the ultrapure nitrogen gas atmosphere. The precursors are confirmed by FT-IR study. The ε-Fe{sub 3}N phase crystallizes in hexagonal structure with unit cell parameters, a = 4.76 Å and c = 4.41 Å. The Co{sub 4}N phase crystallizes in face centred cubic (fcc) structure with unit cell parameters, a = 3.55 Å. The estimated crystallite size for ε-Fe{sub 3}N and Co{sub 4}N phases are 29 nm and 22 nm, respectively. The scanning electron microscopy (SEM) studies confirm the nanocrystalline nature of the materials. The values of saturation magnetization for ε-Fe{sub 3}N and Co{sub 4}N phases are found to be 28.1 emu/g and 123.6 emu/g, respectively. The reduction of magnetic moments in ultrafine materials compared to bulk materials have been explained by spin pairing effect, lattice expansion, superparamagnetic behaviour and canted spin structures at the surface of the particles.

• OSTI ID: 22285180
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 11 Vol. 48; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTALS
FCC LATTICES
IRON CHLORIDES
IRON NITRIDES
MAGNETIC MATERIALS
MAGNETIC PROPERTIES
MAGNETIZATION
NANOSTRUCTURES
PARTICLE SIZE
PRECURSOR
SUPERPARAMAGNETISM
X-RAY DIFFRACTION