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Surface Spin Disorder in Fe3 O4 Nanoparticles Probed by Electron Magnetic Resonance Spectroscopy and Magnetometry.
- Source :
-
IEEE Transactions on Magnetics . Jun2007, Vol. 43 Issue 6, p3091-3093. 3p. 1 Black and White Photograph, 6 Graphs. - Publication Year :
- 2007
-
Abstract
- SQUID magnetometry and electron magnetic resonance (EMR) spectroscopy at 9.28 GHz were employed to probe magnetism and surface spin disorder in Fe3 O4 nanoparticles. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis showed magnetite particles with size ≃8 nm. Magnetization (M) versus temperature studies yielded blocking temperature TB ≃ 170 K in H = 50 Oe. For T > TB, M scales approximately as H/T with μP ≃ 5400 μB as the magnetic moment/particle. At 5 K, the magnitudes of hysteresis loop parameters viz. coercivity Hc ≃ 37 Oe and saturation magnetization M8 = 62 emu/g are considerably smaller than the reported values for larger 150 nm Fe3 O4 particles. In EMR studies, a single symmetric line at g ≃ 2.11 with linewidth ΔH = 850 Oe is observed at 300 K with the g-value and ΔH increasing with decreasing T. These results are interpreted in terms of a disordered surface spin layer of 0.5 nm thickness. [ABSTRACT FROM AUTHOR]
- Subjects :
- *IRON
*MAGNETIC resonance
*SPECTRUM analysis
*MAGNETISM
*ELECTRONS
Subjects
Details
- Language :
- English
- ISSN :
- 00189464
- Volume :
- 43
- Issue :
- 6
- Database :
- Academic Search Index
- Journal :
- IEEE Transactions on Magnetics
- Publication Type :
- Academic Journal
- Accession number :
- 25328825
- Full Text :
- https://doi.org/10.1109/TMAG.2007.894000