Study of the structural and electronic properties of Y1-xGdxBa2Cu3O7-δ superconducting ceramics

Abstract In this work, we studied the effects of Gd substitution on the structural and electronic properties of Y 1−x Gd x Ba 2 Cu 3 O 7−δ $$(x=0.00-0.15)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:mi>x</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.00</mml:mn> <mml:mo>-</mml:mo> <mml:mn>0.15</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> . The compounds were synthesized through a solid-state reaction and characterized by X-ray diffraction (XRD) and Rietveld refinements, resistivity measurements at low temperatures and X-ray photoelectron spectroscopy (XPS). The refinements revealed gadolinium ions gradually substitute yttrium, which strongly influences the crystal structure and critical superconducting temperature (T c ). As the gadolinium content increases, the unit cell volume and T c increase slightly. Through XPS, the chemical orbitals of the constituent elements were successfully identified and the proper incorporation of Gd into the lattice was confirmed. No chemical shifts were observed in the Gd 4d and Y 3d orbitals. Graphical abstract