Magnetoelectric systems could be used to develop magnetoelectric random access memory and microsensor devices. One promising system is the two-phase 3-1-type multiferroic nanocomposite in which a one-dimensional magnetic column is embedded in a three-dimensional ferroelectric matrix. However, it suffers from a number of limitations including unwanted leakage currents and the need for biasing with a magnetic field. Here we show that the addition of an antiferromagnet to a 3-1-type multiferroic nanocomposite can lead to a large, self-biased magnetoelectric effect at room temperature. Our three-phase system is composed of a ferroelectric Na_0.5Bi_0.5TiO₃ matrix in which ferrimagnetic NiFe₂O₄ nanocolumns coated with antiferromagnetic p-type NiO are embedded. This system, which is self-assembled, exhibits a magnetoelectric coefficient of up to 1.38 × 10^–9 s m^–1, which is large enough to switch the magnetic anisotropy from the easy axis (K_eff = 0.91 × 10⁴ J m^–3) to the easy plane (K_eff = –1.65 × 10⁴ J m^–3).

磁电系统可用于开发磁电随机存取存储器和微传感器设备。一个有前途的系统是两相 3-1 型多铁纳米复合材料，其中一维磁柱嵌入在三维铁电基体中。然而，它受到许多限制，包括不需要的泄漏电流和需要磁场偏置。在这里，我们表明在 3-1 型多铁性纳米复合材料中添加反铁磁体可以在室温下产生大的自偏置磁电效应。我们的三相系统由铁电 Na _0.5 Bi _0.5 TiO ₃基质组成，其中亚铁磁性 NiFe ₂ O ₄嵌入了涂有反铁磁性 p 型 NiO 的纳米柱。该系统是自组装的，其磁电系数高达 1.38 × 10 ^–9  s m ^{– 1}，足以切换易轴的磁各向异性 ( K _eff  = 0.91 × 10 ⁴  J m ^–3 ) 到易平面 ( K _eff  = –1.65 × 10 ⁴  J m ^{– 3} )。