| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1591827 | Solid State Communications | 2014 | 4 Pages |
•We have studied theoretically the dielectric function ϵϵ of CuO nanoparticles.•It has two kinks at TN1 and TN2 due to magnetoelectric coupling.•ϵϵ decreases with magnetic field and the kinks disappear.•ϵϵ is suppressed compared to the bulk case due to band gap expansion in the NP.•Ni- or Mn-doping lead to increasing or decreasing of ϵϵ.
Within a microscopic model and a Green׳s function technique we have calculated the temperature and magnetic field dependence of the dielectric function ϵ(T,H)ϵ(T,H) in CuO nanoparticles (NPs) taking into account frustration, single-ion anisotropy, s–d coupling, spin–phonon interaction and linear magnetoelectric coupling. ϵ(T)ϵ(T) shows weak and broad anomalies at the two magnetic phase transition temperatures TN 2 and TN 1 due to the magnetoelectric coupling. ϵ(H)ϵ(H) decreases with increasing of H and the kinks disappear. The changes of ϵϵ with ion doping are discussed. Comparisons to experimental data are made.
