Magnon and Phonon Excitations in Nanosized NiO
Автор
Sildos, I.
Puust, L.
Grabis, J.
Mironova-Ulmane, Nina
Kuzmin, Alexei
Дата
2019Metadata
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Single-crystal, microcrystalline and nanocrystalline nickel oxides (NiO) have been studied by Raman spectroscopy. A new band at ~200 cm-1 and TO-LO splitting of the band at 350–650 cm-1 have been found in the spectra of single-crystals NiO(100), NiO(110) and NiO(111). The Raman spectra of microcrystalline (1500 nm) and nanocrystalline (13–100 nm) NiO resemble those of the single crystals. They all contain the two-magnon band at 1500 cm-1, indicating that the oxides remain at room temperature in the antiferromagnetic
phase. Besides, a new sharp Raman band has been observed at 500 cm-1 in
nanocrystalline NiO. Its temperature dependence suggests the magnetic origin
of the band, possibly associated with the one-phonon–one-magnon excitation
at the Brillouin zone centre.