Observation of Magnetic Field‐Induced and Partially Switchable Electric Polarization in Spin‐Chain FePbBiO 4

The linear magnetoelectric (ME) characteristics of a quasi‐1D spin‐chain compound, FePbBiO 4 , are reported. Two distinct antiferromagnetic (AFM) orders occurring at ≈23 K ( T N1 ) and 12 K ( T N2 ) are verified using magnetization, specific heat, and conspicuous dielectric ( ε ′) anomalies. A striking observation is that no pyrocurrent ( I py ) is detected in the absence of magnetic field ( H ); however, H ‐induced ferroelectric polarization ( P ) at T N1 and P unexpectedly partially switches or reverses below T N2 as reproduced by applying positive and negative electric fields ( E ). The resulting magnetic field and temperature ( H ‐ T ) phase diagram illustrates T ‐dependent H ‐induced spin reorientation and electric P . The interaction between T , H , spin dynamics, and lattice structures is pivotal and is qualitatively discussed and proposed as an explanation for the observed ME nature.