tailieunhanh - Báo cáo " Optical transition of Eu3+ in Mg(Al1-x Eux)2O4 "

The powders of Mg(Al1-xEux)2O4 have been synthesized by sol-gel method. Optical properties of the material were investigated. The nature of lines in luminescence spectra is related to the electron transitions of Eu3+ ions corresponding to different sites in the lattice. The influence of Eu concentration on optical spectra was studied. | VNU Journal of Science Mathematics - Physics 23 2007 84-91 Optical transition of Eu3 in Mg Al1-x Eux 2O4 Trinh Thi Loan Le Hong Ha Nguyen Ngoc Long Department of Physics College of Science VNU 334 Nguyen Trai Hanoi Vietnam Received 29 November 2007 received in revised form 14 December 2007 Abstract. The powders of Mg Al1-xEux 2O4 have been synthesized by sol-gel method. Optical properties of the material were investigated. The nature of lines in luminescence spectra is related to the electron transitions of Eu3 ions corresponding to different sites in the lattice. The influence of Eu concentration on optical spectra was studied. 1. Introduction The rare-earth in general and Eu3 ions in particular - doped materials have a large attention because of their potential use in optical devices such as lasers fiber amplifiers hole-burning high-density memory projection color television. 1 2 3 . Besides the Eu3 ions are well known as an active element for red emitting phosphors. Their spectra may give detailed information about the surrounding of Eu3 ions in a lattice. That is why it is a very useful structural and optical probe. In the present work we report on study of optical properties of trivalent europium ions in powders of Mg Al1-xEux 2O4 synthesized by citrate gel method. Our investigation are mainly focused on the nature of lines corresponding to 5D0 7Fj j 1 2 3 4 emission transitions of Eu3 ions. 2. Experimental The powders of Mg Al1-xEux 2O4 were synthesized by the method described in 4 . Mg NO3 2 Al NO3 3 and Eu NO3 3 solutions were mixed with molar ratio Mg2 Al3 Eu3 1 2 1-x 2x. Citric acid aqueous solution was added into the above solution with molar ratio CA Mii . The solution was vigorously stirred at room temperature. The pH of solution was adjusted to 6 p by adding the ammonia solution. These conditions were drawn from our study of the influence of molar ratio CA Mii and pH of solution on the citrate gel formation. By heating and vigorously stirring .