Abstract
Since the up-conversion phenomenon in rare-earths (REs) doped is strongly affected by the crystal electric field (CF), determining the CF parameters, wave functions, and scheme of the energy levels of the RE multiplets could be crucial to improve and tune the up-conversion efficiency. In this work, the temperature and magnetic field dependent magnetization of hexagonal nanoparticles (NPs) is reported. The data were best fit using the appropriated CF Hamiltonian for the ground state multiplet of ) ions. The , and CF parameters were considered in the Hamiltonian for RE ions located at the hexagonal point symmetry site of the host lattice. These results allowed us to predict an overall CF splitting of ( K) for () and the wave functions and their energy levels for the () ground state multiplet which are in good agreement with the low temperature electron spin resonance experiments. Besides, our measurements allowed us to calculate all the excited CF multiplets that yield to a good estimation of the up-conversion light emission linewidth. The nonlinear optical light emission of the studied hexagonal NPs was also compared with the most efficient up-conversion codoped hexagonal NPs.
- Received 8 September 2017
DOI:https://doi.org/10.1103/PhysRevB.96.165430
©2017 American Physical Society