Correlation Between Microstructural and Magnetic Properties of Tb Implanted ZnO

摘要

We report the results from microstructural and magnetic measurements on 40 keV Tb implanted ZnO single crystals. RBS and channeling measurements for 6.7 × 10~(14) cm~(-2) implanted ZnO showed that around 85% of the Tb atoms occupied Zn substitutional lattice sites. Annealing at 650 °C had a small effect on the Tb location where only 81% of the Tb atoms were located at substitutional lattice sites. Energy-filtered TEM micrographs showed that the Tb atoms were located at an average depth of ~15 nm. Raman spectroscopy results indicated that annealing resulted in a reduction in the implantation induced disorder in the ZnO lattice. Room temperature ferromagnetic order was observed in ZnO:Tb annealed at 650 °C. Superparamagnetic behavior was observed with an average blocking temperature of ~40 K for high Tb concentrations and a distribution in the blocking temperature for low Tb concentrations.