Template Approach for Novel Magnetic--Ferroelectric Nanocomposites
Ni nanowires were electrodeposited into track-etched ferroelectric poly(vinylidene difluoride) (PVDF) polymer nanoporous templates to make multiferroic nanostructured composites. Using ferromagnetic resonance measurements under static voltage bias, we demonstrate a magnetoelectric effect arising fro...
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| Published in | Applied physics express Vol. 4; no. 11; pp. 115001 - 115001-3 |
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| Main Authors | , , , , , , |
| Format | Journal Article |
| Language | English |
| Published |
The Japan Society of Applied Physics
01.11.2011
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| Online Access | Get full text |
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| Summary: | Ni nanowires were electrodeposited into track-etched ferroelectric poly(vinylidene difluoride) (PVDF) polymer nanoporous templates to make multiferroic nanostructured composites. Using ferromagnetic resonance measurements under static voltage bias, we demonstrate a magnetoelectric effect arising from a mechanical coupling between the magnetostrictive and piezoelectric phases. The calculated electric field lines and intensity indicate that PVDF matrix surrounding the surface of the Ni nanowires experiences shear stress. The competing magnetoelastic anisotropy originating from the piezoelectric effects leads to a reduced magnetic anisotropy field along the wire axis. The nanowires packing in the array are found to play a dominant role in the magnetoelectric effect. |
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| Bibliography: | Schematic description of the microstrip transmission line consisting of a metallic ground plane (and cathode), a ferroelectric PVDF polymer template filled with magnetic NWs and the 500 μm wide metallic microstrip line. An adjustable bias voltage up to $\pm 200$ V is applied through the two electrode pads. The calculated electric field lines due to this bias are indicated, as well as the definition of piezoelectric axes. Spatial distribution of electric field intensity in a PVDF--Ni NW nanocomposite ($P= 0.16$%, $h_{\text{Ni}}=0.5$) obtained by considering separately (a) the vertical component and (b) one component of the field in the plane of the PVDF film; (c) same as in (b) with $h_{\text{Ni}}=0.9$. The color scale represents the magnitude of the field in V/m. Variation of the calculated shear strain $\epsilon_{5}$ in PVDF matrix surrounding the lateral surface of the NWs for three NW packing densities, $P = 0.016$, 0.16, and 1.6%, respectively. In all cases, the relative height of the Ni NWs, $h_{\text{Ni}} = 0.75$. The inset shows a schematic representation of the shear strain appearing in the PVDF matrix at the interface with a Ni nanowire with the black arrows indicating the strain orientation. Field sweep microwave absorption spectra recorded at 25 GHz with the field applied parallel to the NWs for an array of Ni NWs ($\varphi\approx 105$ nm, $h_{\text{Ni}}\approx 0.75$, and $P=1.6$%) embedded in a PVDF membrane. Experimental data are shown for zero bias voltage applied (continuous line) as well as for non-zero values ($V=+200$ V, dashed line; $V=-200$ V, dotted line). The inset shows similar FMR transmission spectra for a PVDF--Py sample with $\phi=105$ nm and $P = 1.6$%. |
| ISSN: | 1882-0778 1882-0786 |
| DOI: | 10.1143/APEX.4.115001 |