Correlation Between Magnetic and Electric Properties in the Series of Co_xZn_{1 – x}Fe₂O₄ Nanoparticles

Magnetization dependences of Co_xZn_{1 – x}Fe₂O₄ nanoparticles ($x = 0$, 0.1, 0.2, 0.3, 0.4, 0.5) synthesized with the citrate precursor technique on an external magnetic field and temperature are presented. Ferrimagnetic order in nanoparticles with $x \geqslant 0.2$ appeared at temperatures, T, exceeding room temperature, and in nanoparticles with $x = 0$ and 0.1 at T near 100 K. The saturation magnetization, ${{M}_{s}}$, remnant magnetization, ${{M}_{r}}$, and the coercive force, ${{H}_{c}}$, increase with x increase and the temperature decrease. ${{M}_{s}}$ reached very high value: ${{M}_{s}}$ of NPs with $x = 0.5$ equals to 106.6 emu/g at 100 K while, according to the literature data, ${{M}_{s}}$ of stoichiometric bulk Co ferrite equals to 90 emu/g at 4.2 K. Correlations between concentration dependences of magnetic and electric properties has been revealed and explained qualitatively.