Enhancing the magnetoelectric coupling of Co 4 Nb 2 O 9 [100] by substituting Mg for Co

We report experimental studies on enhancing the magnetoelectric (ME) coupling of Co4Nb2O9 by substituting the non-magnetic metal Mg for Co. A series of single crystal Co4–xMgxNb2O9 (x = 0, 1, 2, 3) with a single-phase corundum-type structure are synthesized using the optical floating zone method, and the good quality and crystallographic orientations of the synthesized samples are confirmed by the Laue spots and sharp XRD peaks. Although the Neel temperatures (TN) of the Mg substituted crystals decrease slightly from 27 K for pure Co4Nb2O9 to 19 K and 11 K for Co3MgNb2O9 and Co2Mg2Nb2O9, respectively, the ME coupling is doubly enhanced by Mg substitution when x = 1. The ME coefficient αME of Co3MgNb2O9 required for the magnetic field (electric field) control of electric polarization (magnetization) is measured to be 12.8 ps/m (13.7 ps/m). These results indicate that the Mg substituted Co4–xMgxNb2O9 (x = 1) could serve as a potential candidate material for applications in future logic spintronics and logic devices.