3 Spin-Polarized Plasmonics: Fresh View …
63
Fig. 3.8 ZFC and FC susceptibility (χ = M/H) for 8.8 nm Co-NP (#25) measured at applied
magnetic field of 20 Oe plotted versus reciprocal temperature, T c = 1394 K is the Curie temperature
for bulk Co. From [2] with permission licensed under CC BY 4.0 https://creativecommons.org
Fig. 3.9 a The particle diameter dependence of the blocking temperature, T b . Dashed and dash-dot
curves show a fitting to the cub dependence, T b ~ V. b The particle diameter dependence of the
anisotropy energy. The dot line is a fitting of reciprocal-cub dependence for [58] and our result. The
bulk value for fcc cobalt is shown by dashed (green) line. From [2] with permission licensed under
CC BY 4.0 https://creativecommons.org
the decrease of anisotropy energy. On the other hand, the increase of particle size
above single-domain size should bring the anisotropy constant towards the balk value
[58]. Figure 3.9b shows that for particles larger than 8 nm the anisotropy energy is
close to the bulk fcc value, 2.7 × 10
6 erg/cm
3 .
Co nanoparticles coated with CoO (or partially oxidized during fabrication) should
exhibit exchange anisotropy due to an interfacial interaction between ferromagnetic
63
Fig. 3.8 ZFC and FC susceptibility (χ = M/H) for 8.8 nm Co-NP (#25) measured at applied
magnetic field of 20 Oe plotted versus reciprocal temperature, T c = 1394 K is the Curie temperature
for bulk Co. From [2] with permission licensed under CC BY 4.0 https://creativecommons.org
Fig. 3.9 a The particle diameter dependence of the blocking temperature, T b . Dashed and dash-dot
curves show a fitting to the cub dependence, T b ~ V. b The particle diameter dependence of the
anisotropy energy. The dot line is a fitting of reciprocal-cub dependence for [58] and our result. The
bulk value for fcc cobalt is shown by dashed (green) line. From [2] with permission licensed under
CC BY 4.0 https://creativecommons.org
the decrease of anisotropy energy. On the other hand, the increase of particle size
above single-domain size should bring the anisotropy constant towards the balk value
[58]. Figure 3.9b shows that for particles larger than 8 nm the anisotropy energy is
close to the bulk fcc value, 2.7 × 10
6 erg/cm
3 .
Co nanoparticles coated with CoO (or partially oxidized during fabrication) should
exhibit exchange anisotropy due to an interfacial interaction between ferromagnetic