Structural and physical properties of nd substituted bismuth cuprates Bi1.7Pb0.3-xNdxSr2Ca3Cu4O12+y


Oezkurt B., Ekicibil A. , Aksan M. A. , Oezcelik B., Yakinci M. E. , Kiymac K.

JOURNAL OF LOW TEMPERATURE PHYSICS, cilt.149, ss.105-118, 2007 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 149
  • Basım Tarihi: 2007
  • Doi Numarası: 10.1007/s10909-007-9500-0
  • Dergi Adı: JOURNAL OF LOW TEMPERATURE PHYSICS
  • Sayfa Sayıları: ss.105-118

Özet

BiPb-2234 bulk samples with nominal composition of the compound Bi1.7Pb0.3-x Nd (x) Sr2Ca3Cu4O12+y (BSCCO) (0.025 <= x <= 0.10) have been prepared by the melt-quenching method. The effects of Nd substitution on the BSCCO system have been investigated by electrical resistance (R-T), scanning electron microscopy (SEM), X-ray diffraction (XRD) and magnetic hysteresis measurements. It has been the BSCCO (2212) low-T-c phase is formed for all the substitution levels, together with the BSCCO (2223) high-T (c) phase. The results obtained suggest that with increasing Nd3+ doping for Pb2+ the (2223) phase existing in undoped BSCCO gradually transforms into the (2212) phase and hence all of the samples have a mixed phase formation. The R-T result of the samples show two-step resistance transition; first transition occurs at 100 K and second in an interval of 80-90 K, depending on the Nd concentration. We have found that the magnetization decreases with increasing temperature in agreement with the general characteristic of the high-T-c materials. The samples exhibit weak field dependence particularly after 2 T and changes on the magnetic hysteresis, M-H curve rather small compared to the conventional superconducting materials. The maximum critical current density, J(c), value was calculated to be 8.51 x 10(5) at 4.2 K and J(c) decreases with increasing temperature and the substitution level.