Structural, dielectric, and magnetic responses in Doped ZnO magnetic nanoparticles for spintronics

The influence of Ce and Co co-doping on the structural, dielectric, and magnetic properties of ZnO nanoparticles annealed in an air/oxygen (O2) environment at 600 °C (six hundred degree Celsius) was investigated. The structural investigation revealed that the addition of Ce and Co to ZnO improved the crystallinity while maintaining the preferred orientation. The SEM study demonstrated that the Ce and Co dopants had no influence on the spherical-like morphology of the particles but merely reduced their size, as confirmed by TEM. It was found that High co-doping of Ce and Co ions into the host ZnO was shown to decrease dielectric characteristics while increasing electrical conductivity. The substitution of Zn ions with Ce and Co ions enhanced the dielectric and electrical conductivities of the samples due to an increase in available charge carriers. A significant change in the hysteresis loop was observed and characterized by the change from the diamagnetic response of ZnO to ferromagnetic (FM) when co-doped with Ce and Co ions. Room-temperature ferromagnetism in the ZnO lattice samples mainly emanated from oxygen vacancies and zinc interstitials. The remanent magnetization increased from 0.421 (electromagnetic unit per gram) to 0.568 emu/g (electromagnetic unit per grame) and then declined dramatically to 0.463 emu/g (electromagnetic unit per grame) when the dopant concentration was changed from 1% (1%) to 2% (2%) and then to 4% (4%). The enhanced dielectric and magnetic properties of the 2% (2%) co-doped sample are strongly correlated to the increase in O2 vacancies. The Ce and Co co-doped is a new work for diluted magnetism semiconductor applications specially in spin-based electronics. In this work, results have demonstrated that Ce and Co co-doped ZnO has tunable RTFM, and the introduction of O2 vacancies is an approach to enhance high-temperature ferromagnetism. These co-doped ZnO nanoparticles are best for spin-based electronics and memristive devices for Resistive Random Access Memory (RRAM) Applications.