Sr14-xCaxCu24O41的芯能级光电子发射谱

测量了准一维1/2自旋的反铁磁体系Sr14-xCaxCu24O41(x=0、3.5、6、7、8.4)多晶样品的芯能级光电子发射谱.各样品的Cu2p3/2的光电子发射谱中主峰峰位位于933.8eV左右,半高宽为3.3eV左右,拟合结果表明,当x=0时,Cu2+和Cu3+的质量分数分别为92.13%和7.87%;而Ca对A位Sr的替代对B位Cu芯能级的影响不明显,Cu2+和Cu3+的质量分数变化很小,估算得该体系中Cu离子的平均化合价为2.08;O1s的光电子发射谱中峰位位于531.0eV左右,并由于Ca对Sr的替代导致在低结合能方向出现一个小的台肩,该台肩来自于Ca-O键的贡献;Ca2p3/2的光电子发射谱中峰位位于346.4eV左右,Sr3d5/2的光电子发射谱中峰位位于133.4eV左右,证明在该体系中Ca和Sr的化合价均为+2价,没有混合价态存在.

Core-level X-ray Photoelectron Emission Spectra of Sr14-xCaxCu24O41

The core-level X-ray photoelectron emission spectra of the quasi-one dimensional spin 1/2 antiferromagnetic system Sr_(14-x)Ca_xCu_(24)O_(41)(x=0, 3.5, 6, 7, 8.4) were measured. The main peak of Cu2p_(3/2) was about 933.8 eV, and the full width of half maximum height was about 3.3 eV. Simulation of Cu2p_(3/2) by XPSPEAK41 shows that the percents of Cu~(2+) and Cu~(3+) in Sr_(14)Cu_(24)O_(41) are 92.13% and 7.87%, no obvious change to Cu2p core-level is observed by the partial substituting Ca for Sr, and the average valence of Cu in this system is estimated to be 2.08. The main peak of O1s is about 531.0 eV, and the weak shoulder toward the low binding energy direction can be considered as the contribution of Ca-O bond. The binding energies of Ca2p_(3/2) and Sr3d_(5/2) indicate that their valence in this system are both +2, without mixed valence.