RESUMO
Fully epitaxial BaTiO(3)/CoFe(2)O(4) ferroelectric/ferromagnetic multilayered nanodot arrays, a new type of magnetoelectric (ME) nanocomposite with both horizontal and vertical orderings, were fabricated via a stencil-derived direct epitaxy technique. By reducing the clamping effect, ferroelectric domain modification and distinct magnetization change proportional to different interfacial area around the BaTiO(3) phase transition temperatures were found, which may pave the way to quantitative introducing of ME coupling at nanoscale and build high density multistate memory devices.
RESUMO
Spontaneous polarization of ferroelectric materials has been for a long time proposed as binary information support, but it suffers so far from destructive readout. A nondestructive resistive readout of the ferroelectric polarization state in a metal-ferroelectric-metal capacitor would thus be advantageous for data storage applications. Combing conducting force microscopy and piezoelectric force microscopy, we unambiguously show that ferroelectric polarization direction and resistance state are correlated for epitaxial ferroelectric Pb(Zr(0.2)Ti(0.8))O(3) nanoscale capacitors prepared by self-assembly methods. For intermediate ferroelectric layer thickness (â¼9 nm) sandwiched between copper and La(0.7)Sr(0.3)MnO(3) electrodes we achieved giant electroresistance with a resistance ratio of >1500 and high switching current densities (>10 A/cm(2)) necessary for effective resistive readout. The present approach uses metal-ferroelectric-metal devices at room temperature and, therefore, significantly advances the use of ferroelectric-based resistive switching.