Effect of Magnetic Field on the Superconducting Phase in the Electron-Doped Metallic Double-Chain Compound Pr₂Ba₄Cu₇O_15-δ

Abstract

We report the magnetotransport and dc magnetic susceptibility of the polycrystalline samples of Pr2Ba4Cu7O 15−δ , to examine the effect of magnetic field on the superconducting phase of the metallic CuO double chain. The resistive critical magnetic field is estimated to be about 21 T at low temperatures from the resistive transition data. On the other hand, the corresponding critical field determined from the magnetization measurements gives rise to a very low value of ∼ 0.3 T at 2 K. These discrepancies in the magnetic response between the resistivity and magnetization data are caused by disappearance of the magnetically shielding effect even in relatively lower fields. In spite of the observation of the resistive drop associated with the superconducting transport currents, the suppression of the diamagnetic signal is probably related to the superconductivity of quasi one-dimensional CuO double-chain. The behavior of Seebeck coefficient in the superconducting Pr2Ba4Cu7O 15−δ is discussed on the basis of the double chain model from the density functional band calculation. PACS numbers: 74.25.Ha,74.90.+n

Enhanced superconducting properties of double-chain based superconductor Pr$_{2}$Ba$_{4}$Cu$_{7}$O$_{15-δ}$ synthesized by citrate pyrolysis technique

“…11 In our previous study, we examined the effect of magnetic fields on the superconducting phase of Pr247. 12 Despite of the resistive drop associated with the superconducting transition, we found that the diamagnetic signal was strongly suppressed as expected in the 1D superconductivity of CuO double chains. We also reported the effect of pressure on magneto-transport properties in the superconducting and normal phases of the metallic double chain compound Pr 2 Ba 4 Cu 7 O 15−δ .…”

“…Here, we define the residual resistivity ratio (RRR) as ρ(300K)/ ρ(30K), For the present samples reduced in vacuum, we obtained the higher RRR values (10 ∼ 12.5), in comparison with the previous data. 12 Furthermore, to check the bulk superconductivity, we performed to measure low-temperature dependences of magnetic susceptibilities χ of the 48-h and 72-h-reduced superconducting samples measured at 5 mT under ZFC scan. Figure 3(b) exhibits diamagnetic signals below T c,on =22.5 K and 24.0 K for the 48-h-reduced and 72-hreduced samples, respectively.…”

“…In addition, the superconducting volume fractions due to the shielding effect are estimated to be 50 ∼ 55% from the ZFC values at 5 K, which are much higher than the previous data (∼ 30%). 12 In the inset of Fig. 3(b) , the magnified data are plot- , b ref.…”

Thermodynamic properties of superconducting and non-superconducting Pr2Ba4Cu7O15-δ compounds with metallic double chains

“…11 In our previous study, we examined the effect of magnetic fields on the superconducting phase of Pr247. 12 Despite of the resistive drop associated with the superconducting transition, we found that the diamagnetic signal was strongly suppressed as expected in the 1D superconductivity of CuO double chains. We also reported the temperature dependence of the Hall coefficient in superconducting Pr247 with a higher T on c ∼ 27 K. 13 Our findings indicated that the superconducting transition temperature increased because the density of doped electron carriers became denser under the reduction treatment, consistent with a theoretical prediction.…”

“…In the x-ray diffraction pattern of polycrystalline Pr 2 Ba 4 Cu 7 O 15−δ synthesized by the citrate pyrolysis method, a clear peak corresponding to the Miller index (004) of Pr247 was observed, but peaks of Pr123 or Pr124 phases were absent (data not shown). 12 Figure 2 plots the temperature dependences of the magnetic susceptibilities of the non-superconducting and superconducting samples under various magnetic fields (up to 5 T). In the as-sintered sample, a typical anomaly in χ occurs near 17 K. This anomaly is associated with an antiferromagnetic transition of the Pr sublattice, as previously reported in Pr123 and Pr124 systems.…”