Size effects on magnetic property of multiferroic DyMn₂O₅ nanorods

DyMn₂O₅ multiferroic nanorods with radial (D) × axial (<L_C>) lengths of 24(9) nm × 46(12) nm, 36(9) nm × 84(26) nm and 111(22) nm × 212(84) nm, were fabricated through the hydrothermal method. The aspect ratio <L_C>/D of the nanorods retained the value 2 at different annealing temperatures (T_a = 400, 800, and 1000 °C for <L_C> = 46, 84, and 212 nm, respectively). Antiferromagnetic magnetic ordering started at approximately 42 K, 42 K, and 50 K for <L_C> = 46 nm, 84 nm, and 212 nm samples, respectively. The saturation magnetic moment (<μ_z>_s), Hc, and Mr decreased as <L_C> increased. The results of magnetic hysteresis experiment implied that magnetic domain sizes decreased as the <L_C> increased. The size effect not only merges the nanorods into larger crystals but also reduces interior magnetic domain sizes.