Süperiletken Bi1.6Pb0.4Sr2Ca2-xSmxCu3Oy bileşiğinin transport ölçümleri

We have investigated the effect of the partial substitutions of Ca by Sm in the Bi-2223 superconducting samples, which are prepared by standard solid-state reaction methods. Magnetoresistivity measurements were made by using four-probe method with DC current of 10mA at 25-130 K temperature interval under constant magnetic field (0.0, 0.3, 0.6T). Electrical resistivity measurements were made by using four-probe methods with DC current of 10mA in the temperature range between 25-130 K. Hence, I-V and magnetic field as function of resistance measurements were done at constant temperatures (70,75, and 80K) under magnetic field which changes from 0.0 T to 0.6 T. Transition temperatures from superconducting state to normal state,Tc, critical current density Jc, activation energy U(H), irreversibility lines are determined from these measurements.According to Arrhenius formula, which is given below;TkUB00)/ln(?=??We obtain that U0 is the slope of arrhenius plot to )/ln(0?? versus 1/T as function of external field. We use linear fits to the apparently linear parts of the curves (in the resistivity parts) to extract activation energies, U0, from the graph.It is observed that the critical temperatures and the activation energies depend on both the Sm content of samples and the magnetic field. Increasing the Sm content shifted the irreversibility temperature to a lower temperature. The critical current density is decreased with increasing Sm content. The electrical resistivity is increased with increasing Sm content and increasing applied magnetic field. Hence, when magnetic field increased is same (this property of type II superconductors) value shifted to low temperature.