Core-Shell Magnetic Morphology of Structurally Uniform Magnetite Nanoparticles

Krycka, Kathryn; Booth, R. A.; Hogg, Charles; Ijiri, Y.; Borchers, J. A.; Chen, Wangchun; Watson, Stephanie S.; Laver, Mark; Gentile, Thomas R.; Dedon, Liv R.; Harris, S.; Rhyne, J. J.; Majetich, Sara A.

doi:10.1103/physrevlett.104.207203

Cited by 145 publications

(148 citation statements)

References 23 publications

(27 reference statements)

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“…6(a) and 6(c), and 6(e)] could be attributed to the increasing alignment of the shell spins to the core magnetization at high applied fields. 32 of the ZFC curve in the low temperature region. The part where magnetization is constantly close to zero is the result of the random orientation of particles' magnetization.…”

Section: Magnetic Characterizationmentioning

confidence: 99%

Morphology influence on nanoscale magnetism of Co nanoparticles: Experimental and theoretical aspects of exchange bias

et al. 2011

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Co-based nanostructures ranging from core/shell to hollow nanoparticles were prepared by varying the reaction time and the chemical environment during the thermal decomposition of Co 2 (CO) 8 . Both structural characterization and kinetic model simulation illustrate that the diffusivities of cobalt and oxygen determine the growth ratio and the final morphology of the nanoparticles. Exchange coupling between Co and Co-oxide in core/shell nanoparticles induced a shift of field-cooled hysteresis loops that is proportional to the shell thickness, as verified by numerical studies. The increasing nanocomplexity, when passing from core/shell to hollow particles, also leads to the appearance of hysteresis above 300 K due to an enhancement of the surface anisotropy resulting from the additional spin-disordered surfaces.

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Section: Magnetic Characterizationmentioning

confidence: 99%

Morphology influence on nanoscale magnetism of Co nanoparticles: Experimental and theoretical aspects of exchange bias

et al. 2011

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“…A crucial issue not taken into account by Néel's model is the different spin dynamics of the uncompensated surface spins with respect to the core ones. 3,4 Moreover, magnetic interparticle interactions of dipolar character, always present to some extent in a powder sample, give rise to complex behavior when coupled with surface effects.…”

Section: Introductionmentioning

confidence: 99%

1H-NMR study of the spin dynamics of fine superparamagnetic nanoparticles

et al. 2012

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We report a broadband 1 H-NMR study of the temperature spin dynamics of nearly monodisperse dextran-coated γ -Fe 2 O 3 magnetic nanoparticles. We observed a maximum in T −1 1 (T ) that decreases in amplitude and shifts toward higher temperatures with increasing field. We suggest that this is related to the progressive superparamagnetic spin blocking of the ferrite core. The data can be explained by assuming a single electronic spin-spin correlation time and introducing a field-dependent distribution of anisotropy energy barriers.

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“…Assuming the spins to be confined to the bc plane, the spin rotation away from the b axis is 30 (2) • at 1.5 K, for a sample 104426-9 of 5-nm goethite particles, and 27.9 (13) • and 27.7(14)…”

Section: Discussionmentioning

confidence: 99%

“…When the particle size is decreased to the nanoscale, the magnetic structure can differ from that of the corresponding bulk material because of broken exchange-bonds at the particle surface and because of surface contributions to the magnetic anisotropy [11][12][13][14]. The change in magnetic structure as well as dynamics in magnetic nanoparticles can be of crucial importance for their applications and, hence, determining the magnetic structure of nanoparticles is important.…”

Section: Introductionmentioning

confidence: 99%