Pyroelectric current and magnetoelectric coupling measurements on polycrystalline samples of the quadruple perovskite (LaMn$_{ 3}$)Mn$_{ 4}$O$_{ 12}$ give evidence of ferroelectricity driven by the antiferromagnetic ordering of the $B$-site Mn$^{ 3+}$ ions at $T_{ N,B}$=78 K with record values of remnant electric polarization up to $P$=0.56 $\mu$C cm$^{ -2}$. X-ray diffraction measurements indicates an anomalous behavior of the monoclinic $\beta$ angle at $T_{ N,B}$, which suggests that $P$ lies in the $ac$-plane, where the moments are collinear, so we conclude that exchange striction is the mechanism of spin-driven ferroelectricity. Polarization values $\sim$3 $\mu$C cm$^{ -2}$ are expected in single crystals, which would open the avenue towards practical multiferroic applications.
Categories: cond-mat.mtrl-sci