High pressure synthesis of late rare earth RFeAs(O,F) superconductors; R = Tb and Dy

Abstract

New TbFeAs(O,F) and DyFeAs(O,Fand 36 K for Gd. 8 High pressure and temperature synthesis is known to stabilise many late rare earth analogues of early rare earth solid compounds. This approach has been used

Structural trends from a consistent set of single-crystal data ofRFeAsO(R=La, Ce, Pr, Nd, Sm, Gd, and Tb)

“…8, the intra-plane distance approaches the inter-plane distance of the arsenic atoms preventing a further shrinkage of the structure. Consequently, all RE FeAsO compounds with smaller rare-earth metal atoms (RE = Dy, Ho, ...) have to be synthesized under external pressure as described in literature 9,28,29 . The iron-arsenic layer in TbFeAsO can thus be considered as a section of a body centered cubic packing of Fig.…”

Superconductivity above 50 K in LnFeAsO1-y (Ln = Nd, Sm, Gd, Tb, and Dy) Synthesized by High-Pressure Technique

“…In particular for Ln ¼ Tb and Dy, superconducting samples can be synthesized only using high-pressure technique. Furthermore, to our knowledge, there is no report on the successful synthesis of single-phase Dy-and Tb-based superconductors with their T c 's exceeding 50 K. [16][17][18] Accordingly, it is not clear yet whether the lower T c of the heavier Ln-based samples is really intrinsic to the system, or due to the poorer sample quality. The relationship between Ln and T c in LnFeAsO based materials is therefore still open.…”

Suppression of the superconducting transition ofRFeAsO1−xFx(R=Rodgers1, Penny2, Marcinkova3 et al. 2009Phys. Rev. BSelf Cite241180View full textAdd to dashboardCite

“…11 Initial results for RFeAsO 1−x F x ͑R = Tb and Dy͒ were published elsewhere. 12 Both materials were found to be superconducting with maximum T c 's of 46 and 45 K, respectively. Little difference in superconducting properties between samples with nominal compositions of x = 0.1 and 0.2 were observed, and the x = 0.2 materials were generally of lower phase purity, and so the x = 0.1 composition was used in subsequent syntheses.…”