Experimental study of magneto-superconductor RuSr2Eu1.5Ce0.5Cu2O10: Effect of Mo doping on magnetic behavior and Tc variation

Abstract

Mo doped ruthenocuprates Ru1-xMoxSr2Eu1.5Ce0.5Cu2O10 are synthesized for x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0, and their magnetic and superconducting properties are studied. It has been found that the magnetic transition temperature TZFCpeak, which corresponds to the appearance of weak ferromagnetic effect, decreases from its value of 75 K for x = 0.0 to 22 K, 25 K and 18 K, respectively for the x = 0.2, 0.4 and 0.6 samples. Another finding is that the magnetic susceptibility reduces at TZFCpeak by a factor of about 6, 85 and 413 for x = 0.2, 0.4, and 0.6 respectively. The samples of x = 0.8 and 1.0 are found to have no magnetic or superconducting effects. The values of the superconducting transition temperature are obtained from the resistivity versus temperature data. An important result is that Tc increases by 4.5 K and 7.0 K for x = 0.2 and 0.4 respectively, and then decreases by 17 K for x = 0.6. The observed variation of Tc with x has been explained in terms of a theory which combines the effects of weakening magnetic behavior and reducing carrier concentration in a phenomenological manner. The resulting theory is found to provide a good agreement with the observed value of Tc.