IMPACT OF Ce DOPING ON THE MAGNETIC AND TRANSPORT PROPERTIES OF Y_1-xCe_xSr₂Ru_0.9Cu_2.1O_7.9; x = 0.05 AND 0.1

The magnetic and transport properties of lightly Ce doped, Y_1-xCe_xSr₂Ru_0.9Cu_2.1 O_7.9(x = 0.05 and 0.1) samples have been studied and their results are compared with the pristine rutheno-cuprate, YSr₂Ru_0.9Cu_2.1O_7.9. The electron doping due to Ce⁴⁺ for Y³⁺ ion impacts on the physical properties of the present system. The tetragonal stabilized samples exhibit magneto superconducting properties under zero field cooled condition (H = 10 Oe) and the diamagnetic onset transition, T_d shift slightly towards higher temperature with the increase of "x". Weak antiferromagnetic like hysteresis curves are seen for these samples at 2 K in the magnetic field strength up to ±10 kOe and the magnetization moment, M(μ_B/Ru) decreases with increase of "x". While the magnetic property of the present system is due to canted Ru moments, the superconducting signal originates from CuO₂ plane. Through electrical resistivity measurements we observe that none of the samples exhibit bulk superconductivity down to 2 K. However the x = 0.05 sample reveals lowest resistivity in the entire temperature range than x = 0 and 0.1 samples. The isothermal magnetoresistance, MR(H) measured at different temperatures vary with tuning of "x". While x = 0.1 doped sample shows lower -MR(~ 8%), the pristine sample exhibits maximum -MR(45%) at 2 K under ±90 kOe field condition.