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We report here on the preparation, X-ray diffraction with Rietveld refinement, resistivity and AC magnetic susceptibility measurements of (Y1-xEux)(SrBa)Cu3O6.94. Each sample was subject to two types of heat treatment: oxygen annealing [O] and argon annealing followed by oxygen annealing [AO]. For each x, the [AO] treatment increases the orthorhombicity ε (for 0 ≤ x ≤ 1), Tc (for x ≥ 0.45) and by 6 K to 87 K for x = 1 [AO], and the distance d[Cu(1)-Sr/Ba] (decrease Tc) for x <; 0.4 and decrease it (increase Tc) for x >; 0.4. In the normal state, the [AO] treatment reduced the linear resistivity parameters indicating a diminution of the interaction of carrier charges with phonons. There was a remarkable improvement in the shielding effect S (amplitude of χ'(T)) in the case of the samples [AO] at all T <; Tc and for any applied field for x >; 0.5. For each x and heat treatment, S(x) decreases when Hdc and the temperature increase. Remarkable correlations were observed. A combination of several factors such as decrease in d[Cu(1)-(Sr/Ba)] ; increase in cationic and chain oxygen ordering; pSh and in-phase purity for the [AO] samples may account for the observed data.
Date of Publication: June 2011