Anisotropic magnetotransport of superconducting and normal state in an electron-doped Nd1.85Ce0.15CuO4−δ single crystal

Abstract

The anisotropic properties of an optimally doped Nd1.85Ce0.15CuO 4−δ single crystal have been studied both below and above the critical temperature Tc via the resistivity measurement in magnetic field H up to 12 T. By scaling the conductivity fluctuation around the superconducting transition, the upper critical field Hc2(T ) has been determined for field parallel to the c-axis or to the basal ab-plane. The anisotropy factor γ = H ab c2 /H c c2 is estimated to be about 8. In the normal state (50 ≤ T ≤ 180 K), the magnetoresistance (MR) basically follows an H 2 dependence and for H c it is almost 10 times larger than that for H ab. Comparing with hole-doped cuprates it suggests that the optimally doped Nd1.85Ce0.15CuO 4−δ cuprate superconductor has a moderate anisotropy.

Pinning mechanism in electron-doped HTS Nd$_{1.85}$Ce$_{0.15}$CuO$_{4-\delta }$ epitaxial films

“…By studying the behavior of the H field near T c , the in-plane and out-of-plane coherence lengths ξ ab and ξ c and the anisotropy factor γ were estimated. It results that ξ ≈ 20 c Å and ξ ≈ 100 ab Å, in agreement with the values reported in the literature [16,17], whereas, γ, evaluated as ∥ H c2 ab/ ∥ H c2 c, is quite large, around 30. As reported elsewhere [16], this value strongly depends on the crystalline quality of the compound, then also the oxygenʼs distribution into the NCCO structure can contribute to its anisotropy.…”

“…A discrete number of papers have been dedicated to the study of transport and magnetic properties in electron-doped copper oxide superconductors [1][2][3][4][5][6], whereas very few studies have been carried out about their pinning properties [7,8]. Nevertheless, this kind of investigation is very important in defining the possible applications of these materials.…”

Transport anomalies and quantum criticality in electron-doped cuprate superconductors

“…The above method is thus not applicable in electron-doped ones. A scaling of the fluctuation conductivity σ flu (H, T) has been used to extract H c2 (T) [160][161][162][163]. In this method, the σ flu was obtained by subtracting the extrapolated normal state conductivity from the total conductivity.…”

Strong anisotropy effect in an iron-based superconductor CaFe0.882Co0.118AsF

“…Huge experiments have revealed that the FeSCs belong to a family with an unconventional pairing mechanism within FeAs(Se) layers. Information regarding the upper critical field H c2 and its anisotropy in superconductivity can be used as a fingerprint to understand the unconventional superconducting mechanism and to promote practical applications [2][3][4]. In addition, bidimensionality, which is represented by a rather high anisotropy between the ab-plane and c axis, is believed to be a very important factor for the occurrence of strong correlation physics and even high-T c superconductivity [5][6][7][8][9].…”