Achieving superconductivity through reductive treatments of YSr2(Cu1−xFex)3Oy

O’Brien, Jeanne E.; Óesterreicher, H.; Taylor, R. D.

doi:10.1007/bf02653018

Cited by 1 publication

(1 citation statement)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is known that a parent compound YSr 2 Cu 3 O 7 will not form using a standard synthesis procedure [5,6], but that substitution of Fe [7,8] for Cu resulted in singlephase materials in the range 0.13 < x ≤ 0.33 [8][9][10][11]. A large amount of Fe in YBa 2 (Cu 1−x Fe x ) 3 O y prevents the development of superconductivity [4,9,11,12] when the materials are prepared by the conventional slow cooling method. Exposure to a reducing environment (T ≥ 1000 K) followed by a short-term (1 h) low-temperature (T < 700 K) reoxidation treatment has been shown [1,13,14] to enhance T c and superconducting volume fractions in the Fe-doped YBCO system.…”

Section: Introductionmentioning

confidence: 99%

Superconductivity through redox treatments of

O’Brien¹,

Óesterreicher²

1998

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Superconductivity is developed through controlled redox treatment variation in a material with unusually high Fe concentration. The dependence of the structural, magnetic, and superconductive properties of ; x = 0.13 or x = 0.167) on annealing conditions is explored. Sintered bulk materials are prepared with an extended exposure at T = 1000 K. This procedure is designated OP for oxygenating preparation and all materials treated in this way show no signs of superconductivity above 5 K. Subsequently, Gd getter annealing is used to control reductions at T = 1000 K for 4 days followed by reoxidation at 800 K for 1 h. For x = 0.167 and z = 0, a strong reduction (y = 6.3) reoxidation procedure resulted in the development of superconductivity with . As the Ca content increases, successively milder reductive conditions must be employed to obtain superconductors. A local thermodynamic model based on the stabilities of various Fe cluster arrangements and oxidative states predicts the changes expected on Ca substitution. It is argued that Fe in a cluster with 5-fold O coordination is not detrimental to superconductivity while 4-fold coordination quenches holes because of the uncompensated nature of this low O coordination.

show abstract