Two-dimensional correlation spectroscopy analysis of Raman spectra of NiO nanoparticles

We report two-dimensional correlation spectroscopy (2D-COS) analyses of the Raman spectra of NiO nano particles over a temperature range from 100 to 300 K. 2D-Raman correlation spectra suggest strong correlation of the phonon spectral intensity variation with the magnetic ordering in NiO nanoparticles. It is revealed that the antiferromagnetic ordering affects the TO phonon anisotropy in NiO nanoparticles. We elucidate the complex spectral features of two-magnon (2 M) bands by performing appropriate 2D-COS model simulations. Significant spin-phonon coupling in NiO nanoparticles is supported by our results. High energy magnon-magnon interaction tails are also found to be involved in the spin-phonon coupling. 2D-COS analyses provide rich information regarding the nature of the phonon and magnon excitations of NiO nanoparticles.

Automated summary

In this study, we used two-dimensional correlation spectroscopy (2D-COS) to analyze the Raman spectra of NiO nanoparticles in the temperature range of 100 to 300 K. The 2D-Raman correlation spectra showed a strong correlation between the phonon spectral intensity variation and magnetic ordering in the NiO nanoparticles. It was found that the antiferromagnetic ordering affected the TO phonon anisotropy in the NiO nanoparticles. Complex spectral features of two-magnon (2 M) bands were elucidated through appropriate 2D-COS model simulations. The results supported the presence of significant spin-phonon coupling in the NiO nanoparticles, with high-energy magnon-magnon interaction tails also being involved in the spin-phonon coupling. 2D-COS analyses provided rich information about the phonon and magnon excitations in NiO nanoparticles.