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IJPAP Vol.45 [2007] >
IJPAP Vol.45(10) [October 2007] >
| 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
Bhattacharyya, Sayan |
| Keywords: | Nanoparticle
Iron-nickel nitride
Mössbauer
Spin canting
Superparamagnetism |
| Issue Date: | Oct-2007 |
| Publisher: | CSIR |
| IPC Code: | 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. |
| Page(s): | 834-838 |
| ISSN: | 0019-5596 |
| Source: | IJPAP Vol.45(10) [October 2007]
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