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Full-Text Articles in Physics
Mechanical Writing Of Ferroelectric Polarization, Haidong Lu, C.-W. Bark, D. Esque De Los Ojos, J. Alcala, Chang-Beom Eom, G. Catalan, Alexei Gruverman
Mechanical Writing Of Ferroelectric Polarization, Haidong Lu, C.-W. Bark, D. Esque De Los Ojos, J. Alcala, Chang-Beom Eom, G. Catalan, Alexei Gruverman
Alexei Gruverman Publications
Ferroelectric materials are characterized by a permanent electric dipole that can be reversed through the application of an external voltage, but a strong intrinsic coupling between polarization and deformation also causes all ferroelectrics to be piezoelectric, leading to applications in sensors and high-displacement actuators. A less explored property is flexoelectricity, the coupling between polarization and a strain gradient. We demonstrate that the stress gradient generated by the tip of an atomic force microscope can mechanically switch the polarization in the nanoscale volume of a ferroelectric film. Pure mechanical force can therefore be used as a dynamic tool for polarization control …
Complex Domain Structure In Relaxed Pbtio3 Thick Films Grown On (100)Csrruo3//(100)Srtio3 Substrates, Shintaro Yasui, Yoshitaka Ehara, Satoru Utsugi, Mitsumasa Nakajima, Hiroshi Funakubo, Alexei Gruverman
Complex Domain Structure In Relaxed Pbtio3 Thick Films Grown On (100)Csrruo3//(100)Srtio3 Substrates, Shintaro Yasui, Yoshitaka Ehara, Satoru Utsugi, Mitsumasa Nakajima, Hiroshi Funakubo, Alexei Gruverman
Alexei Gruverman Publications
Domain structures of epitaxial PbTiO3 films grown on (100)cSrRuO3//(100)SrTiO3 substrates by metalorganic chemical vapor deposition were investigated by x-ray diffraction (XRD) and piezoresponse force microscopy (PFM) techniques. It was found that with increasing film thickness, the domain structure changed from simple (001) polarization orientation to a complicated mixture of (001) and (100) orientations. PFM mappings showed that in the thicker films (~1100 nm), the zigzag (001)/(100) domain boundaries made an angle of approximately 87° instead of 90° typically observed in (001)/(100) domain patterns in thinner (<300 nm) films. Full-relaxed tilting angle θ1+ θ2+θ3 …
Tunnel Electroresistance In Junctions With Ultrathin Ferroelectric Pb(Zr0.2ti0.8)O3 Barriers, Daniel Pantel, Haidong Lu, Silvana Goetze, Peter Werner, Dong Jik Kim, Alexei Gruverman, Dietrich Hesse, Marin Alexe
Tunnel Electroresistance In Junctions With Ultrathin Ferroelectric Pb(Zr0.2ti0.8)O3 Barriers, Daniel Pantel, Haidong Lu, Silvana Goetze, Peter Werner, Dong Jik Kim, Alexei Gruverman, Dietrich Hesse, Marin Alexe
Alexei Gruverman Publications
In ferroelectric tunnel junctions, the ferroelectric polarization state of the barrier influences the quantum-mechanical tunneling through the junction, resulting in tunnel electroresistance (TER). Here, we investigate tunnel electroresistance in Co/PbZr0.2Ti0.8O3/La0.7Sr0.3MnO3 tunnel junctions. The ferroelectric polarization in tunnel junctions with 1.2-1.6 nm (three to four unit cells) PbZr0.2Ti0.8O3 thickness and an area of 0.04 μm2 can be switched by about 1 V yielding a resistive ON/OFF-ratio of about 300 at 0.4 V. Combined piezoresponse force microscopy and electronic transport investigations of these junctions reveal …
Electric Modulation Of Magnetization At The Batio3/La0.67sr0.33mno3 Interfaces, H. Lu, Thomas A. George, Yong Wang, Ihor Ketsman, John D. Burton, C.-W. Bark, Sangjin Ryu, Dong Jik Kim, J. Wang, Christian Binek, Peter A. Dowben, Andrei Sokolov, C. B. Eom, Evgeny Y. Tsymbal, Alexei Gruverman
Electric Modulation Of Magnetization At The Batio3/La0.67sr0.33mno3 Interfaces, H. Lu, Thomas A. George, Yong Wang, Ihor Ketsman, John D. Burton, C.-W. Bark, Sangjin Ryu, Dong Jik Kim, J. Wang, Christian Binek, Peter A. Dowben, Andrei Sokolov, C. B. Eom, Evgeny Y. Tsymbal, Alexei Gruverman
Alexei Gruverman Publications
We report large (>10%) magnetization modulation by ferroelectric polarization reversal in the ferroelectric-ferromagnetic BaTiO3/La0.67Sr0.33MnO3 (BTO/LSMO) heterostructures. We find that the electrically induced change in magnetization is limited to the BTO/LSMO interface but extends about 3 nm deep into the LSMO layer—far beyond the expected screening length of metallic LSMO. It is suggested that this effect is due to a metal-insulator transition occurring at the BTO/LSMO interface as a result of electrostatic doping.