Synthesis and physical characterization of superconductivity–magnetism crossover compound RuSr2EuCeCu2O10−δ

Abstract

We carefully studied the nonsuperconducting sample of the magneto-superconducting RuSr 2 (Eu 1-x Ce x )Cu 2 O 10-δ series with composition RuSr 2 EuCeCu 2 O 10-δ. This compound seems to exhibit a complex magnetic state as revealed by host of techniques like resistivity, thermopower, magnetic susceptibility and MR measurements. The studied compound exhibited ferromagnetic like M(H) loops at 5, 20 and 50 K, and semiconductor like electrical conduction down to 5 K, with -MR 7Tesla of up to 4% at low temperatures.The -MR 7Tesla decreases fast above 150 K and monotonically becomes close to zero above say 230 K.Below, 150 K -MR 7Tesla decreases to around 3% monotonically down to 75 K, with further increase to 4%at around 30K and lastly having a slight decrease below this temperature. The thermopower S(T) behavior closely followed the -MR 7Tesla steps in terms of d(S/T)/dT slopes. Further, both MR 7Tesla steps and d(S/T)/dT slopes are found in close vicinity to various magnetic ordering temperatures (T mag. ) of this compound.PACS No. 74.72. Jt, 74.25. Bt, 75.80. +q

X-ray photoelectron spectroscopy of superconductingRuSr2Eu1.5Ce0.5Cu2Manju1, Awana2, Kishan3 et al. 2006Phys. Rev. BSelf Cite15220View full textAdd to dashboardCite

“…Analysis of Cu 2p spectra in terms of a configuration interaction model provides a quantitative description of the gross electronic structures of these ruthenocuprates. 8 with Ln= Gd, Sm, or Eu has triggered a large amount of research activities in the field of such ruthenocuprates. These systems exhibit ferromagnetic order at a relatively high Curie temperature of about 100-140 K and become superconducting at a significantly lower critical temperature of about 15-40 K depending on the synthesis method.…”

“…The details of the synthesis procedures are described elsewhere. 7,8 Polycrystalline samples of Sr 2 RuO 4 were synthesized by the conventional ceramic route using stoichiometric quantities of high purity SrCO 3 and ruthenium oxide. They were thoroughly ground and the mixture was heated at 600°C for 24 h to avoid Ru evaporation, then at 930°C for 24 h, then at 1050°C for 24 h, and finally at 1200°C for 36 h with intermittent grindings.…”