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|Title:||Mössbauer and magnetic studies for the coexistence of Ɛ-Fe₃₋xNixN and ϒ'-Fe₄₋yNiyN phases in Fe-Ni-N nanoparticles|
|Authors:||Gajbhiye, N S|
|Series/Report no.:||B82B, G01J3/28|
|Abstract:||Nanocrystalline Ɛ-Fe3-xNixN (x = 0.5-0.8) particles are synthesized by precursor technique and nitridation of decomposed products in NH₃ (g) at 673 K. A small fraction of fcc ϒ'-Fe₄₋yNiyN phase (space group: P43m) is precipitated along with the formation of Ɛ-Fe₃₋xNixN hexagonal structure (space group: P63/mmc). The Mössbauer spectrum at room temperature for all the compositions shows the presence of superparamagnetic doublet, which is attributed to Ɛ-Fe₃₋xNixN phase and two sextets corresponding to the corner Fe (Fec) and fcc Fe (Fef), in ϒ'-Fe₄₋yNiyN. The added Ni atoms preferentially substitute the Fec positions. The isomer shift, quadrupole splitting and hyperfine field values vary with the Ni content. The zero-field cooled (ZFC) and field-cooled (FC) curves indicate strong interparticle interactions and surface spin-glass-like state is realized from the low temperature features. The magnetization curves are saturated at 5 K, due to the dominating ferromagnetic nature of the ϒ'-Fe₄₋yNiyN phase.|
|Appears in Collections:||IJPAP Vol.45(10) [October 2007]|
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