Modulating the reversibility of electric polarization in Al-doped Y-type hexaferrites

Abstract Controlling and modulating the magnitude and signs of electric polarization in multiferroics are very important for practical applications. The magnetoelectric effect in multiferroic materials enables the control and tailor of electric polarization by a magnetic field or vice versa. However, there are rare investigations about the mutual control of the magnitude and signs of electric polarization in multiferroics. Here, we successfully synthesized single crystals of Y-type hexaferrites Ba0.8Sr1.2Co2Fe12-xAlxO22 (x = 0 and 1.08) via flux method. The magnetization, magnetodielectric and magnetoelectric properties were investigated. We found that Al-doping increased the conical magnetic structure transition temperatures and enhanced the magnetoelectric properties. Most importantly, both samples exhibited reversal and non-reversal polarizations at low and high temperatures, respectively. In addition, Al-doping can stabilize the non-reversal ferroelectric polarization, possibly originating from the different field-dependent magnetic structure transitions.