Effect of substituting Ce at the Ca site on the high-temperature superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}
- Tata Institute of Fundamental Research, Homi Bhabha Road, Bombay 400005 (India)
We have investigated the system Bi{sub 2}Sr{sub 2}Ca{sub 1{minus}{ital x}}Ce{sub {ital x}}Cu{sub 2}O{sub 8+{delta}} (0{le}{ital x}{le}0.5) to study the effect of substituting Ce for Ca on superconductivity in the Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} system ({ital T}{sub {ital c}}=90 K). It is observed that, on 25 at.{percent} substitution of Ce for Ca, superconductivity is completely suppressed. This is relatively faster suppression of superconductivity compared to that seen on substituting other rare earths for Ca where {approximately}50 at.{percent} substitution is required to suppress superconductivity. Magnetic susceptibility of the Bi{sub 2}Sr{sub 2}Ca{sub 1{minus}{ital x}}Ce{sub {ital x}}Cu{sub 2}O{sub 8+{delta}} compounds is found to be weakly temperature dependent showing a small rise at low temperatures and a shallow minima at about 200 K. These results suggest the possible existence of Ce in a tetravalent state rather than in a trivalent state in this system. X-ray-diffraction studies on these compounds indicate a decrease in the {ital c} lattice parameter with increased substitution of Ce. This is consistent with nearly tetravalent Ce ion replacing the Ca{sup 2+} ion since the size of Ce{sup 3+} is comparable to that of Ca{sup 2+}, while that of Ce{sup 4+} is smaller. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 278690
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 53, Issue 5; Other Information: PBD: Feb 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Growth and properties of oxygen- and ion-doped Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8+. delta. single crystals
Enhancement of the superconducting transition temperature of TlSr sub 2 CaCu sub 2 O sub 7 by yttrium and vanadium substitutions