Spin-phonon coupling effects in antiferromagnetic Cr ₂O ₃ nanoparticles

In the present work we use Raman microscopy to investigate the size effect of spin-phonon coupling in antiferromagnetic Cr ₂O ₃ nanoparticles. The peculiarities of the dependency of the phonon wave number on temperature (with a relatively weak peak at 293 cm-1) can be attributed to the spin-phonon coupling. The variation with temperature of the spin-phonon mode develops when the antiferromagnetic state is near the ordering temperature of the Cr spins. The observations can be reasonably well interpreted by describing the order parameter. A shift in frequency is caused by a strong spin-phonon interaction in Cr ₂O ₃. The obtained s-ph coefficients are found to be consistent with the strain, where raising the strain results in weakening of the s-ph coupling.