Superconductivity of F-substitutedLnOBiS₂(Ln=La, Ce, Pr, Nd, Yb) compounds

Abstract

compounds were synthesized by solid-state reaction. The samples were characterized by x-ray diffraction measurements and found to have the ZrCuSiAs crystal structure. Electrical resistivity and magnetic susceptibility measurements were performed on all of the samples and specific heat measurements were made on those with Ln = La, Ce, and Yb. All of these compounds exhibit superconductivity in the range 1.9 K -5.4 K, which has not previously been reported for the compounds based on Ce, Pr, and Yb. The YbO 0.5 F 0.5 BiS 2 compounds was also found to exhibit magnetic order at ~2.7 K that apparently coexists with superconductivity below 5.4 K.

Superconducting Anisotropies of F-Substituted LaOBiSe2 Single Crystals

“…BiS 2 -layered sulfide superconductors, such as Bi 4 O 4 S 3 1) , RO 1-x F x BiS 2 (R=La, Ce, Pr, Nd, Yb) [2][3][4][5][6] and Sr 1−y La y FBiS 2 7) , have been extensively studied. However, there are fewer papers about BiSe 2 -layered selenide.…”

Charge Fluctuations in the NdO1−xFxBiS2 Superconductors

“…The new phonon mediated BiS 2 superconductors, LnO 1−x F x BiS 2 (Ln=La, Ce, Nd, Pr and Yb) [1,2] and Bi 6 O 4 S 4 (SO 4 ) 1−x [3], have attracted considerable attention recently because of the interplay of spatial disorder, phonon anomalies and superconductivity. Charge carriers are introduced either by electron doping or by defects in the spacer layers that sandwich the BiS 2 superconducting planes.…”

Synthesis and Properties of SmO0.5F0.5BiS2 and Enhancement in Tc in La1–ySmyO0.5F0.5BiS2

“…[7][8][9][10] For example both these systems crystallize in the same space group (P4/nmm), they have layered structure with a charge reservoir layer (LnO) and a superconducting layer (BiS 2 , Fe-As), their parent phases are semiconducting or poorly conducting and, most importantly, they become superconducting upon electron-doping (doping F -for O 2-or a tetravalent ion for Ln). [9][10][11][12][13][14][15][16][17] Superconductivity by fluorine -doping in LaO 1-x F x BiS 2 was first reported by Mizuguchi et al (T c ~ 2.5 K) 9 ( T c ~10 K could be achieved by high pressure synthesis). 9 Superconductivity in LnO 1-x F x BiS 2 with Ln = Ce, Pr, Nd and Yb also followed soon.…”

“…9 Superconductivity in LnO 1-x F x BiS 2 with Ln = Ce, Pr, Nd and Yb also followed soon. [10][11][12][13][14][15][16] T c is enhanced by chemical pressure [18][19][20] or external applied pressure [22][23][24][25][26][27] as observed for LnOFeAs 28 for example in LnO 1-x F x BiS 2 , a slight enhancement in T c has been reported by substituting Se at the S sites or by inter-mixing rare earth ions. [18][19][20][21] Hole doping via alkali earthmetal-substitution at Ln-site did not yield superconductivity.…”