Chemistry of electron doped Ln{sub 2-x}Ce{sub x}CuO{sub 4} superconductors
- Univ. of Texas, Austin, TX (United States)
The electron doped Ln{sub 2{minus}x}Ce{sub x}CuO{sub 4} (Ln = lanthanide) oxides have intergrowth structures consisting of superconductively active CuO{sub 2} sheets alternating with inactive (Ln, Ce){sub 2}O{sub 2} fluorite layers along the c-axis. Stabilization of such intergrowth structures requires bond length matching across the intergrowth interface. The bond length matching criterion causes a monotonic decrease in the Ce solubility limit from x = 0.24 to x = 0.15 as the size of Ln{sup 3+} decreased from Ln=La{sub 0.5}Nd{sub 0.5} to Ln=Gd. Annealing in N{sub 2} atm of Ln{sub 2{minus}x}Ce{sub x}CuO{sub 4} at temperatures above 900 degrees C creates oxygen vacancies and the number of vacancies decreases with increasing Ce content. The value of x at which a semiconductor to superconductor transition occurs in Ln{sub 2{minus}x}Ce{sub x}CuO{sub 4} increases with decreasing size of Ln{sup 3+} due to an increasing Madelung energy caused by a decreasing Cu-O bond length.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 433418
- Journal Information:
- Journal of Electronic Materials, Journal Name: Journal of Electronic Materials Journal Issue: 10 Vol. 22; ISSN JECMA5; ISSN 0361-5235
- Country of Publication:
- United States
- Language:
- English
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