Spin–phonon interaction effects in pure and Fe-doped antiferromagnetic Cr2O3 nanoparticles

• We have studied theoretically the magnetic and phonon properties of Cr2O3 nanoparticles.
• It is shown that with decreasing of particle size the magnetization increases whereas the Neel temperature decreases.
• The phonon energy ωω of the A1g mode has a kink at TN due to the strong spin–phonon interaction.
• ωω increases with decreasing of particle size.
• Fe-dopant concentration reduces the phonon energy.

We have studied the temperature and size dependence of the magnetic and phonon properties of pure and Fe-doped antiferromagnetic Cr2O3 nanoparticles using a microscopic model and a Green's function technique. The magnetization M increases whereas the Neel temperature TN decreases with decreasing of particle size. The phonon energy ωω has a kink at TN due to the strong spin–phonon interaction. It increases with decreasing of particle size. Fe-dopant concentration reduces ωω.