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Magnetoelectric multiferroic Properties of BTO/CFO/BTO thin films grown on Pt/TiO 2 /SiO 2 /Si. [Display omitted] • Multiferroic thin films were successfully grown using PLD. • Improved magnetoelectric properties for BTO-CFO-BTO. • Interesting multiferroic and magnetoelectric properties. A magnetoelectric multiferroic bi-phase system with robust ferroelectric and ferro/ferri-magnetism response at room temperature would be ideally suitable for microelectronics, memory devices, and for spintronic applications. BaTiO 3 /CoFe 2 O 4 /BaTiO 3 (BTO/CFO/BTO) heterostructured films were pulsed laser deposition grown on Pt(1 1 1)/TiO 2 /SiO 2 /Si substrates. High quality polycrystalline films were grown by thermal annealing at 750 °C, at an oxygen partial pressure of 100 mTorr for 1 h. Crystal quality and phase formation information was monitored using X-ray diffraction (XRD). XRD confirm the growth of polycrystalline heterostructures and the coexistence of both perovskite BTO and spinel CFO phases in heterostructures. In order to obtain robust magnetoelectric coupling, we studied the tri-layer structure as a representative ferroelectric/ferrimagnetic/ferroelectric system. We report the ferroelectric, leakage current behavior, ferrimagnetic, and frequency dependent ME properties of the films. Ferroelectric BTO and ferrimagnetic inverse spinel CFO nature is also confirmed using the piezoresponse force microscopy and magnetic force microscopy measurements. These nanostructures exhibit high saturation polarization (Ps ∼ 99.86 µC/cm2), saturation magnetization (Ms ∼ 51.48 emu/cm3), and a strong ME coupling coefficient of ∼ 274 mV/cm-Oe with a bias magnetic field of + 90 Oe, anda frequency of 1 kHz revealing them as prospective candidates for multifunctional applications. [ABSTRACT FROM AUTHOR]

Highlights • Engineered ferroelectric-ferromagnetic heterostructures showed good magnetic response. • Heterostructures are found to sustain a magnetocaloric effect for broad temperature. • These effects are attributed to epitaxial strains and magnetoelectric coupling. • These results may help in development of spintronics and solid state refrigerators. Abstract This study reports the magnetocaloric effect (MCE) and piezoresponse of integrated ferroelectric-ferromagnetic heterostructures of PbZr 0.52 Ti 0.48 O 3 (PZT) (5 nm)/Bi-Sr-Ca-Cu 2 -O X (BSCCO) (5 nm)/La 0.67 Sr 0.33 MnO 3 (LSMO) (40 nm)/MgO (0 0 1). Magnetic and pizoresponse behavior of the heterostructures are found to be governed by magneto-electric coupling and induced lattice strains. In addition, a maximum MCE is studied using Maxwell equations from both Field Cooled (FC) and Zero Field Cooled (ZFC) magnetization data. Maximum MCE entropy change (|Δ S |) of 42.6 mJkg−1K−1 (at 258 K) and 41.7 mJkg−1K−1 (at 269 K) are found corresponding to FC and ZFC data, respectively. The variation in maximum entropy change and corresponding temperatures for FC and ZFC data revealed that the application of a magnetic field can significantly contribute towards tuning of the MCE. Interestingly, these multilayered structures are found to sustain MCE over a broad temperature range, which makes them attractive for improved solid-state energy conversion devices. [ABSTRACT FROM AUTHOR]

Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO3 (BFO) thin films have been deposited on Pt/TiO2/SiO2/Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical "butterfly-shaped" loop were observed in BSFCO films with an effective piezoelectric constant (d33) ~94 pm/V at 0.6 MV/cm. High dielectric constant ~900 and low dielectric loss ~0.25 were observed at room temperature. M-H loops have shown relatively high saturation magnetization ~35 emu/cm³ at a maximum field of H ~20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films. [ABSTRACT FROM AUTHOR]

Abstract: Raman scattering from one-magnon excitation has been observed for the first time in epitaxial BiFeO3 thin films grown on (111) SrTiO3 substrates. The intensities and the frequency of the magnon mode at 18.9cm−1 (M1) showed a discrepancy at the characteristic temperatures of ∼140 and 200K and the magnon mode at 27.9cm−1 (M2) disappeared at ∼200K suggesting spin-reorientation (SR) transition in the epitaxial BFO film. The dc susceptibility measurement showed a large discrepancy near these two temperatures evidently elucidating the spin-reorientation transition mechanism. The partial spectral weight of the magnon modes is believed to be transferred to the lowest phonon mode appearing at 72.8cm−1 and higher magnon mode M2 disappearing near 200K reveal magnon–phonon coupling near to SR transition. [Copyright &y& Elsevier]