Growth and characterization of Bi3.15Nd0.85Ti2.95Hf0.05O12/La0.67Sr0.33MnO3 composite film with strong magnetoelectric effect by chemical solution deposition under moderate crystallization temperature

Abstract

Using chemical solution deposition method, La0.67Sr0.33MnO3 (LSMO) and Bi3.15Nd0.85Ti2.95Hf0.05O12 (BNTH) layers were successively fabricated onto (001) LaAlO3 (LAO) substrates, and then BNTH/LSMO ferromagnetic-ferroelectric composite films with a 2-2 layered type structure were obtained. The LSMO ferromagnetic layer was epitaxially grown on the LAO substrate and showed the low resistivity of 5.0 × 10−3 Ω cm. It was not only used as a seed layer to induce the oriented growth of BNTH ferroelectric layers, but also as a bottom electrode to measure ferroelectric/magnetoelectric (ME) properties. The effects of crystallization temperature on the orientation degree, the surface morphology, and the dielectric and ferroelectric performances of the composite films were investigated. The composite film crystallized at 730 °C has the largest remnant polarization (Pr) of 35.0 μC/cm2, the lowest leakage current density of 1.35 × 10−7 A/cm2 and the high saturated magnetization (Ms) of 370 emu/cm3. The composite film also exhibits a strong ME response in the absence of DC bias magnetic field. Its ME voltage coefficient, αE, gradually increases from zero with the increasing of the AC magnetic field frequency, and eventually reaches 35.8 V/cm·Oe at 100 kHz.