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采用时间微分扰动角关联方法测量了LaFeO3纳米中的电四极超精细相互作用。扰动角关联探针核57140La58140Ce由139La(n,γ)140La反应产生,实验只观察到一个La晶位的四极相互作用。在室温下20nm、40nmLaFeO3以及晶体LaFeO3的四极相互作用频率ω0分别为:687.4Mrad/s、698.3Mrad/s和742.9Mrad/s,频率分布宽度系数σ分别为:0.014、0.009和0.001,电场梯度不对称系数η=0。实验数据表明,电场梯度主轴与晶轴方向一致;样品具有菱方结构,晶体到纳米发生菱方向正交结构转变,纳米尺度越小,越趋于正交结构;由于邻近核的扰动,随纳米颗粒增大,四极相互作用频率分布宽度系数σ变小,晶体时最小。
The superfine quadrupole interaction in LaFeO3 nanocrystals was measured by the time differential perturbation angle correlation method. The perturbation angle related probe nucleus 57140La58140Ce was produced by the reaction of 139La (n, γ) 140La. The experiment only observed the quadrupole interaction of one La site. At room temperature, the quadrupole interaction frequency ω0 of 20nm, 40nm LaFeO3 and LaFeO3 crystal are 687.4Mrad / s, 698.3Mrad / s and 742.9Mrad / s respectively, and the frequency distribution width coefficients σ are 0.014,0.009 and 0.001, respectively. The asymmetry coefficient η = 0. The experimental data show that the main axis of the electric field gradient is in the same direction as the crystal axis. The sample has a rhombic structure, and the orthorhombic structure changes from rhombic to nanocrystalline. The smaller the nanoscale, the more orthogonally oriented. Due to the perturbation of the adjacent nuclei, The particle size increases and the frequency distribution width coefficient σ of the quadrupole interaction becomes smaller and the crystal size is the smallest.