Multiferroic and phonon properties of pure and ion doped CoCr2O4 - Bulk and nanoparticles

Using a microscopic model we have studied different properties of pure and ion doped CoCr2O4 - bulk and NPs. The magnetization M-s and the Curie temperature T-c decrease with decreasing particle size. By Fe doping M-s and T-c increase with enhancing Fe concentration x whereas by Mg doping we obtain the opposite effect. In the first case there is a compressive strain, in the second one - a tensile strain due to the different radii of the doping ions compared to the host ones. This leads to different exchange interaction constants in the doped states. The polarization P-s increases with increasing Fe doping concentration x. Two anomalies are observed in the specific heat C-p, at T-c = 98 K, and T-s = 25 K, which are not so sharp applying h. The temperature, magnetic field, size and doping dependence of the phonon energy omega(0) = 685 cm(-1) and damping are also investigated. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Using a microscopic model, the properties of pure and ion doped CoCr2O4 - bulk and NPs were studied. It was found that the magnetization and Curie temperature decrease with decreasing particle size, and different effects were observed with Fe and Mg doping due to the different strains caused by doping ions. The polarization increases with increasing Fe doping concentration, and anomalies in specific heat were observed at specific temperatures.