Ferrimagnetism and abnormal spin–lattice coupling in dilute magnetic ferroelectric (Bi_0.46Na_0.46Ba_0.08)TiO₃:Co

We have investigated the low-temperature magnetism and spin–lattice coupling in (Bi_0.46Na_0.46Ba_0.08)TiO₃:Co in order to understand the magnetoelectric effect in such artificially synthesized dilute magnetic ferroelectrics. It is revealed that the as-prepared (Bi_0.46Na_0.46Ba_0.08)TiO₃:Co at Co content of 20%～30% exhibits fascinating ferrimagnetism which is robust against magnetic field, the abnormal spin–lattice coupling characterized by a negative magnetostriction effect; and the suppressed magnetic moment within the temperature range of 30 K～50 K is identified. These magnetic behaviours at low temperatures can be explained by the competition between the ferrimagnetic response and the magnetic moment suppression induced by the abnormal spin–lattice coupling effect. Finally, the ferroelectric and magnetodielectric properties are also discussed.