Thickness and frequency dependence of magnetoelectric effect for epitaxial La0.7Sr0.3MnO3/BaTiO3 bilayer

• The thickness and frequency dependence of the FM and FE properties is obvious.
• There is a particular thickness dependence of ME behavior from 0.1 to 100 kHz.
• The αE is at least one order of magnitude higher than others due to a rather low εr.
• The αE of the 100nm LSMO/BTO bilayers is higher than that of others.

The epitaxial La0.7Sr0.3MnO3/BaTiO3 (LSMO/BTO) bilayer films were grown on (0 0 1) oriented (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 (LSAT) substrate by pulsed laser deposition technique. The effect of film thickness on its ferromagnetic properties, ferroelectric properties and magnetoelectric (ME) effect was investigated. Measurements of thickness and frequency dependence (0.1—100 KHz) of the ME voltage coefficient (αE) and phase angle (Δθ) demonstrated a strong ME coupling at room temperature for all bilayer films. The value of αE approached the maximum (140 mV/cm Oe) when the thickness of LSMO and BTO films was all equal to 100 nm, which was at least one order of magnitude higher than previous reported similar structure due to a rather low dielectric constant of BTO film. The value of αE decreased with the increasing bilayer film thickness when both the LSMO and BTO film thickness were higher than 100 nm. It was a combined effect of the thickness dependence for the magnetic and electric properties.