High pressure amplify the structural characteristic of calcium-doped Bi-2201 phase

Ca-doped Bi-2201 samples obtained by optimized preparation methods increase the highest onset of superconducting transition T (c, onset) up to 77 K. Raman experiments show that Ca-doping makes the O Sr peak shift from 643 to 647 cm −1 , which indicates that the O Sr and surrounding atoms become closer. In addition, pressure is used to amplify the effects of doping in the structural characterizations. High-pressure angle dispersive x-ray diffraction (ADXRD) results indicate that the Ca-doped Bi-2201 sample has a tighter atomic packing than the pure sample, which results in a lower Raman peak position shift rate under compression. Combining the ambient data with the high-pressure structural analysis, the apical oxygen of the CuO 6 octahedron is closer to CuO 2 plane and adjusts CuO 2 plane distortion, resulting in the increasing of T (c, onset) in Ca-doped Bi-2201 samples. Graphical Abstract Pressure can confirm the structural details of the high T c Ca-doped Bi-2201 phase by amplifying its structural characteristic.