Mg doping effect on the magnetic properties of Y-type hexaferrite Ba0.5Sr1.5Zn2−xMgxFe12O22

• First report systematically the magnetism of Mg-doped Ba0.5Sr1.5Zn2Fe12O22.
• The range for intermediate-III phase increases significantly as x increases to 2.0.
• Magnetic-field-induced ferroelectric phase can be stabilized at 0 T by Mg2+.

The microstructure and magnetic properties of Mg-doped Ba0.5Sr1.5Zn2Fe12O22 hexaferrites synthesized by the solid state method are investigated. All the undoped and doped samples show a sharp screw proper spin phase to collinear ferrimagnetic spin phase transition above room temperature, and transition temperature increases distinctly with Mg doping. It is noteworthy that all the samples exhibit another magnetic phase transition at a lower temperature T1, which is associated with the longitudinal conical to the proper screw phase transition. The transition temperature T1 can be modulated by varying Mg content, indicating that the longitudinal conical spin phase is stabilized by the Mg-substitution. The saturation magnetization at room temperature increases to a maximum with Mg content x = 0.8 and then decreases with x. The variations of magnetic properties can be ascribed to the difference in the preferential site for Zn and Mg and different distribution of Fe3+ ions over tetrahedral and octahedral sites. It is worth noting that the range for the intermediate-III phase increases significantly as x increases to 2.0, suggesting that Mg-doped samples may be display field-induced ferroelectric order at temperature close to RT and in wide magnetic-field regions. The room-temperature M-H curves at lower applied field indicate that magnetic-field-induced ferroelectric phase can be stabilized at zero magnetic field by the substitution by Mg2+ for Zn2+. The Mg-doped hexaferrites Ba0.5Sr1.5Zn2Fe12O22 may be potential candidates for applying in magnetoelectric devices.