Large Magnetoelectric Coupling in the Thin Film of Multiferroic CuO

• Published in: ACS omega 2020-09, Vol.5 (36), p.22883-22890
• Main Authors: Goswami, Sudipta, Dey, Koushik, Chakraborty, Supriyo, Giri, Saurav, Chowdhury, Ujjal, Bhattacharya, Dipten
• Format: Article
• Language: English
• ISSN: 2470-1343; 2470-1343
• DOI: 10.1021/acsomega.0c02211

We report observation of large magnetoelectric coupling in an epitaxial thin film of multiferroic CuO grown on the (100)­MgO substrate by the pulsed laser deposition technique. The film is characterized by X-ray diffraction, transmission electron microscopy, and Raman spectrometry. The crystallographic structure of the film turns out to be monoclinic (space group C2/c) with [111]­CuO||[100]­MgO “out-of-plane” epitaxy and “in-plane” domain structure. The lattice misfit strain is found to vary within ±1–3%. The dc resistivity, magnetization, dielectric spectroscopy, and remanent ferroeletric polarization have been measured across 80–300 K. The dielectric constant is found to decrease by >20% under a moderate magnetic field of ∼18 kOe while the remanent ferroelectric polarization, emerging at the onset of magnetic transition (T N ∼ 175 K), decreases by nearly 50% under ∼18 kOe field. These results could assume importance as the strain-free bulk CuO does not exhibit magnetoelectric coupling within such magnetic field regime. The strain-induced large magnetoelectric coupling in the CuO thin film would generate new possibility of further strain tuning to observe room-temperature magnetoelectric multiferroicity suitable for scores of applications such as memories, sensors, energy-harvesting devices, generators, amplifiers, and so forth.