Preparation, structure, and peritectic transition of RBa{sub 1.5}Sr{sub 0.5}Cu{sub 3}O{sub y} (R = La, Nd, Sm, Eu, Gd, Dy, Ho, and Y) superconductors
- Tamkang Univ., Tamsui (Taiwan, Province of China). Dept. of Chemistry
A series of single-phase RBa{sub 1.5}Sr{sub 0.5}Cu{sub 3}O{sub y} (T = La, Nd, Sm, Eu, Gd, Dy, Ho, and Y) compounds with a triple-perovskite unit cell has been prepared by solid-state reaction method. Samples with a larger radius of the R ion (R = La and Nd) are tetragonal, whereas those with a smaller radius of the R ion (R = Sm, Eu, Gd, Dy, Ho, and Y) are orthorhombic. Unit-cell parameters of RBa{sub 1.5}Sr{sub 0.5}Cu{sub 3}O{sub y} decrease monotonically with a decrease of the radius of the R ion. A maximum at R = Nd, Sm, and Eu is found in the peritectic transition temperature (t{sub p}), the amount of oxygen loss ({Delta}w) in this transition, and the enthalpy of fusion ({Delta}H{sub f}), respectively. An increase in the {Delta}H{sub f} is correlated with increasing t{sub p} for the respective orthorhombic and tetragonal phases of RBa{sub 1.5}Sr{sub 0.5}Cu{sub 3}O{sub y} compounds. {Tc} of the title compounds gradually increased from 52 to 86 K with a decrease in the radius of the R ion.
- OSTI ID:
- 638343
- Journal Information:
- Materials Research Bulletin, Vol. 33, Issue 8; Other Information: PBD: Aug 1998
- Country of Publication:
- United States
- Language:
- English
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