The vacancy-type defects in Nb-doped SrTiO 3 and in undoped SrTiO 3, annealed in H 2 flow, were investigated by means of positron lifetime and 2D angular correlation of annihilation radiation (ACAR) experiments. The calculations of the lifetime of positron were performed by using atomic superposition (AT-SUP) method. The results showed that positrons annihilate from a free state in the Nb-doped SrTiO 3. The trapping centers in the annealed sample were found to be oxygen vacancies V o associated with relaxation of the surrounding ions. Moreover, the momentum distributions of the samples studied were correlated to the variation of their electronic structure. It was proposed from the drastic change in the momentum distribution upon introduction of V o, that 2D-ACAR technique is a sensitive tool for acquiring information on the electronic and bond structure of the perovskite-oxides.
|ジャーナル||Physica Status Solidi (A) Applications and Materials Science|
|出版ステータス||Published - 2006 2 1|
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