Room-Temperature Multiferroicity and Magnetoelectric Couplings in (Co0.75al0.25)2(Fe0.75mg0.25)O4 Spinel Films

The electric field manipulation of a magnetic order is a key feature of advanced information technologies and the development of room-temperature multiferroic magnetoelectrics remains an important task. In this work, we report novel single-phase magnetoelectric (ME) films consisting of a (Co 0.75 Al 0.25 ) 2 (Fe 0.75 Mg 0.25 )O 4 spinel solid solution. The (Co 0.75 Al 0.25 ) 2 (Fe 0.75 Mg 0.25 )O 4 thin films display a switchable polarization and magnetization with a remnant polarization of about 2.1 µC cm –2 and a remnant magnetization of about 82.0 emu cm –3 at 300 K. The films also exhibit large piezoelectric responses. Electric field control of magnetism is detected, the magnetization modulation reaches 8.5% at room temperature with an electric field of 500 kV cm −1 , revealing the existence of magnetoelectric coupling. We believe that the substitutions of Al 3+ and Mg 2+ cations at the spinel sublattices might induce atomic ordering and local distortion, which give rise to the ferroelectricity and ME effect in the (Co 0.75 Al 0.25 ) 2 (Fe 0.75 Mg 0.25 )O 4 thin films. The electric field-induced charge modulation may also contribute to the observed magnetoelectric effect, which likely results from the migration and redistribution of oxygen vacancies in the prepared nanofilms. The findings of this work can stimulate research studies on the development of room temperature multiferroics and magnetoelectrics based on the spinel ferrite compounds