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研究了不同元素(Gd,Sm)掺杂和不同掺杂浓度的Nd1.85-xRxCe0.15CuO4±δ(R=Gd,Sm)单晶样品的X射线衍射、傅里叶变换红外光谱和电阻率.X射线衍射结果表明掺杂没有杂质峰,且峰的半高宽度很小,说明两掺杂体系的单晶样品品质很好.两体系晶格常数c均随着掺杂量的增加而降低,其中Gd掺杂体系的降低速率明显大于Sm.对于Gd掺杂,随着掺杂量的增加红外光谱逐渐向高频移动,而Sm掺杂红外光谱峰位几乎保持不变.这表明用Gd取代Nd会使Cu-O键变短,而用Sm取代Nd后Cu-O键键长几乎不变.电阻率的测量结果发现随着掺杂量的增加两体系的超导转变温度TC均被压制,载流子局域化效应均增强.而对于Gd掺杂,超导转变温度TC被更强烈的压制,载流子局域化效应更强,这一现象与两掺杂体系的晶胞体积的变化情况一致,也可能与和费米面上电子态密度随掺杂量的改变有关.
The X-ray diffraction, Fourier transform infrared spectra and resistivity of Nd1.85-xRxCe0.15CuO4 ± δ (R = Gd, Sm) single crystal samples doped with different elements (Gd, Sm) and different doping concentrations .X-ray diffraction results show that there is no impurity peak doping, and the width of the peak half-width is small, indicating that the two-doped single crystal sample quality is good.The two system lattice constant c decreases with increasing doping amount , Of which Gd doping system decreased significantly faster than Sm.For Gd doping, as the doping amount increases, the infrared spectrum gradually moves to high frequency, while the Sm doping infrared peak position remains almost unchanged.This shows that with Gd The substitution of Nd causes the Cu-O bond to be shortened, whereas the substitution of Sm for Nd results in little change in the Cu-O bond length.The resistivity measurements show that the superconducting transition temperature TC of both systems is increased with the doping amount Suppression and carrier localization are enhanced.While Gd doping, the superconducting transition temperature TC is more strongly suppressed, carrier localization effect is stronger, and this phenomenon with two doping system unit cell The change of volume is consistent, and it may be related to the change of doping quantity with the density of electrons on Fermi surface.