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oe1(光电查) - 科学论文

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?? 中文（中国） ▾

  • Fast and Simultaneous Determination of Soil Properties Using Laser-Induced Breakdown Spectroscopy (LIBS): A Case Study of Typical Farmland Soils in China

    摘要： This work provides a new paradigm for designing a laser crystal requiring a broad luminescent spectrum through spontaneous polarization and local structural disorder. The grown complex ferroelectric crystals Nd-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (Nd:PMNT) have a broad emission spectrum with a full width at half-maximum value of 30 nm, much larger than typical Nd laser crystals (Nd:YAG ≈ 0.8 nm). The internal mechanism of spectral broadening in complex ferroelectric crystals was analyzed using the con?guration coordinate. The shift of the peak site in the 4F3/2 → 4I11/2 transition with temperature was a?ected by structural changes, consistent with the change in dielectric and ferroelectric properties. The family of complex ferroelectric crystals could be an abundant treasure for Nd femtosecond laser crystals requiring a broad luminescent spectrum.

    关键词： local disorder,spontaneous polarization,ferroelectric crystals,Pb(Mg1/3Nb2/3)O3,Nd-doped,broad bandwidth emission

    更新于2025-09-11 14:15:04

  • First-principles study of the ordered structures of the single crystal PMN(0.75)-PT(0.25) and their ferroelectric characteristics

    摘要： For the various PMN(0.75)-PT(0.25) ordered structures, first principles density functional studies using local density approximation (LDA) framework and augmented projected augmented wave (PAW) pseudopotentials. All possible 20-atom ordering along the [001]-, [011]- and [111]- directions are considered in the ab-initio code VASP. Also, we conducted linear response with density functional perturbation theory (DFPT) which is implemented in the VASP to compute the electronic dielectric tensors and piezoelectric tensors. The polar response is strongly dependent of the ionic ordering. Some PMN(0.75)-PT(0.25) ordered structures show strong piezoelectric characteristics.

    关键词： first-principles calculation,piezoelectric characteristics,Pb(Mg1/3Nb2/3)O3-PbTiO3,ordered structure

    更新于2025-09-10 09:29:36