Enhanced polarization and magnetoelectric response in Tb1− xHo xMnO3.

A series of manganites Tb1− xHo xMnO3 (0≤ x≤0.6) with orthorhombic structure are synthesized and detailed investigations on their multiferroicity are performed. Successive magnetic transitions upon temperature variation are evidenced for all the samples, and both the Mn3+spiral spin ordering and rare-earth spin ordering are suppressed with increasing x. A significant enhancement of both the polarization and magnetoelectric response within 0.2< x<0.4 is observed, which may probably result from the shortening of the spiral-spin-ordering period, due to the competition between the spiral spin order and E-type antiferromagnetic order. This argument is supported by further theoretical calculations based on the two e g-orbital double-exchange model. [ABSTRACT FROM AUTHOR]