Effect of Nd substitution on magnetoelectric properties of Sm2BaCuO5

We have investigated the magnetic and magnetoelectric properties of solid solutions in the green phase region of the 211-cuprate system Sm2−xNdxBaCuO5 (x = 0.2, 0.4 and 0.6). These compounds crystallize in the centrosymmetric orthorhombic (Pnma) structure. Upon substitution of Nd, the antiferromagnetic ordering temperature of Cu2+ ions (TN1 = 24 K) and Sm3+/Nd3+ ions (TN2 = 5 K) remain unchanged. Dielectric anomalies appear at TN1 under applied magnetic field, whose magnitude increases with field, and at TN2 = 5 K under zero magnetic field for all three compounds. Applied magnetic fields induce electric polarization at TN1 that vary linearly with magnetic fields. While the polarization decreases below TN2 in x = 0 and 0.2, it is enhanced for the samples with x = 0.4 and 0.6. Interestingly, an additional anomaly is observed in dielectric and electric polarization data at 23 K for the composition x = 0.4 under the magnetic fields. Our study reveals that the substitution of Nd significantly modifies the electrical properties due to changes in the interactions between 4f–3d moments.