Magnetoelectric coupling in CoFe₂O₄‐Pb(Zr_0.2Ti_0.8)O₃ coaxial nanofibers

Abstract

In this work, we reported the fabrication and magnetoelectric coupling properties of the multiferroic CoFe 2 O 4-PbZr 0.2 Ti 0.8 O 3 (CFO-PZT) coaxial nanofibers synthesized by electrospinning technique. The coaxial structure of nanofibers was demonstrated by magnetic force microscope and transmission electron microscope. The multiferroic properties of coaxial nanofibers have been revealed by magnetic hysteresis loops and piezoresponse amplitude butterfly curves and phase hysteresis loops. The as-prepared coaxial nanofibers show an effective piezoelectric coefficient d 33 of 30 pm/V and a saturated magnetization of 12 emu/g. Their magnetoelectric response has been probed by means of the localized changes in magnetization after poling the domains of the composite system. A static, large converse magnetoelectric coupling coefficient of 1.2 × 10 −8 s/m was obtained in a single CFO-PZT nanofiber.

Large room temperature magnetoelectric response in quasi 1–2 nanocomposite films on mica substrate

“…Thus, the converse ME coefficient α C was calculated to be 1.43 × 10 −8 s/m. This ME coefficient was close to that of CFO–PZT coaxial nanofibers (1.2 × 10 −8 s/m) 3 and significantly higher compared to those of the [Ni‐P(VDF‐TrFE)] nanowires (∼10 −11 s/m) 5 and BaTiO 3 –CFO nanocomposite films (4.9 × 10 −9 s/m) 82 …”

“…Synthesis details for CFO nanofibers can be found in our previous reports. 3,31 PZT film was deposited on SRO/NFO/mica substrate with CFO nanofibers at 600 • C with an oxygen partial pressure of 15 Pa. After the deposition of PZT, the CFO nanofibers were covered by the PZT film layer, as shown in Figure 1A. Pt electrodes with a diameter of 100 µm were deposited on the surface of these composite films by sputtering.…”

“…1,2 Bulk materials often exhibit lower than anticipated properties due to cracks, leakage, and other limitations. 3,4 However, it is expected that these limitations can be overcome with the use of nanocomposites composed of ferroelectric and ferromagnetic phases. Enhancing the ME coupling effect by increasing the contact area between the two phases is important, as the coupling is transmitted through the strain at the contact interface of the two phases.…”

“…8,9 However, heterostructure nanocomposites grown on substrate usually suffer from a large clamping effect from the stiff, large volume, underlying substrate, which weakens or even suppresses in-plane structural response under either magnetic or electric field-induced stress, thus in turn, reducing the ME coupling response. Compared with the clamped thin films, nanostructures such as nanoparticles, nanowires, and nanofibers were introduced into the ME composites to form 0-3 and 1-3 nanocomposites, 3,[10][11][12][13] which provided a variety of mechanical connectivity between the ferroelectric and ferromagnetic constituents and thus enhanced both the stress transfer efficiency and ME coupling response due to the large surface-to-volume ratio of the nanostructures and the increased interfacial surface area connecting the ferroelectric and ferromagnetic phases. One-dimensional nanofibers assembled by nanoparticles also overcame the leakage issue found in the 1-3 vertical heterostructures, in which the conductive ferromagnetic nanowires may contact with the top and bottom electrodes and result in large leakage currents.…”

MOKE and MFM on magnetically coated nanofiber mats: Transferring well‐known methods to uncommon samples

“…MFM measurements, on the other hand, have the problem that with increasing surface roughness in fiber-based materials, distinguishing between magnetic and topographic features becomes more and more complicated, while at the same time, a high surface roughness in the range of several hundred nanometers necessitates modification of the measurement parameters in such a way that the lateral resolution is significantly reduced [19]. Thus, only a few attempts to measure MFM on single nanofibers are reported in the literature [20][21][22][23][24], with a first preliminary study from our group indicating that MFM on nanofiber mats can generally give a magnetic signal [25].…”