Pressure effect on the Tc of La2-xSrxCuO4 and La1.4-xSrxNd0.6CuO4 at x near 1/8
The x~1/8 anomaly in the La-based cuprates had been interest since the discovery of high-Tc (superconducting transition temperature) superconductors. Recently, the stripe phase which has attracted considerable attention in connection with many experiments, like neutron scattering, Raman and infrared(IR) spectra, Hall effect, thermoelectric power and magnetic susceptibility, etc. These results indicate that a crossover from one- to two-dimensional charge transfer accurs at x~1/8.
In this thesis, we synthesize two series of p-type superconductors La2-xSrxCuO4 and La1.4-xSrxNd0.6CuO4 by solid-state reaction. It has been well known that there is a marked drop in Tc - x phase diagram at x~1/8 in both systems. It is possible that this phenomenon is related to the stripe phase. So we select some samples with different doping level x nearly the drop to initiate the experiment of high pressure effect. We apply pressure with isotropic direction to squeeze unit cell and try to know the relation between Tc to stripe phase.
The experimental results show that the Tc of superconducting sample increases, however, the La1.4-xSrxNd0.6CuO4 (x~1/8) sample is still not superconducting at high pressure. It has been shown that, the additional pressure can¡¦t suppress the structure to effect stripe phase or the intensity of pressure is not high enough.
Advisor:Hsiung Chou; Hung-Duen Yang; Jiunn-Yuan Lin
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:la2 xsrxcuo4 la1 4 xsrxnd0 6cuo4
Date of Publication:01/07/2005