P
Padraic Shafer
Researcher at Lawrence Berkeley National Laboratory
Publications - 155
Citations - 6919
Padraic Shafer is an academic researcher from Lawrence Berkeley National Laboratory. The author has contributed to research in topics: Magnetization & Antiferromagnetism. The author has an hindex of 30, co-authored 130 publications receiving 5095 citations. Previous affiliations of Padraic Shafer include Infineon Technologies & University of California, Berkeley.
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Journal ArticleDOI
Above-bandgap voltages from ferroelectric photovoltaic devices
S. Y. Yang,Jan Seidel,Jan Seidel,Byrnes Steven J,Byrnes Steven J,Padraic Shafer,Chan-Ho Yang,Marta D. Rossell,Pu Yu,Ying-Hao Chu,James F. Scott,Joel W. Ager,Lane W. Martin,Ramamoorthy Ramesh,Ramamoorthy Ramesh +14 more
TL;DR: A fundamentally different mechanism for photovoltaic charge separation is reported, which operates over a distance of 1-2 nm and produces voltages that are significantly higher than the bandgap.
Journal ArticleDOI
Observation of polar vortices in oxide superlattices
Ajay K. Yadav,Ajay K. Yadav,Christopher T. Nelson,Christopher T. Nelson,Shang-Lin Hsu,Shang-Lin Hsu,Zijian Hong,James D. Clarkson,Christian M. Schlepütz,Anoop R. Damodaran,Padraic Shafer,Elke Arenholz,Liv R. Dedon,Deyang Chen,Ashvin Vishwanath,Ashvin Vishwanath,Andrew M. Minor,Andrew M. Minor,Andrew M. Minor,Long Qing Chen,James F. Scott,Lane W. Martin,Lane W. Martin,Ramamoorthy Ramesh,Ramamoorthy Ramesh +24 more
TL;DR: In this paper, the authors used the competition between charge, orbital and lattice degrees of freedom in superlattices of alternating lead titanate and strontium titanate layers to produce complex topologies of electrical polarization.
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Enhanced ferroelectricity in ultrathin films grown directly on silicon.
Suraj Cheema,Daewoong Kwon,Daewoong Kwon,Nirmaan Shanker,Roberto dos Reis,Shang-Lin Hsu,Shang-Lin Hsu,Jun Xiao,Haigang Zhang,Ryan Wagner,Adhiraj Datar,Margaret McCarter,Claudy Serrao,Ajay K. Yadav,Golnaz Karbasian,Cheng-Hsiang Hsu,Ava J. Tan,Li Chen Wang,Vishal Thakare,Xiang Zhang,Apurva Mehta,Evguenia Karapetrova,Rajesh V. Chopdekar,Padraic Shafer,Elke Arenholz,Elke Arenholz,Chenming Hu,Roger Proksch,Ramamoorthy Ramesh,Jim Ciston,Sayeef Salahuddin,Sayeef Salahuddin +31 more
TL;DR: This work shifts the search for the fundamental limits of ferroelectricity to simpler transition-metal oxide systems—that is, from perovskite-derived complex oxides to fluorite-structure binary oxides—in which ‘reverse’ size effects counterintuitively stabilize polar symmetry in the ultrathin regime.
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Electric field-induced magnetization switching in epitaxial columnar nanostructures
F. Zavaliche,Haimei Zheng,L. Mohaddes-Ardabili,S. Y. Yang,Q. Zhan,Padraic Shafer,E. Reilly,Rajesh V. Chopdekar,Y. Jia,Paul K. Wright,Darrell G. Schlom,Y. Suzuki,Ramamoorthy Ramesh +12 more
TL;DR: Direct evidence for room-temperature magnetization reversal induced by an electric field in epitaxial ferroelectric BiFeO3-ferrimagnetic CoFe2O4 columnar nanostructures is presented.
Journal ArticleDOI
Domain Engineering for Enhanced Ferroelectric Properties of Epitaxial (001) BiFeO Thin Films
Ho Won Jang,Daniel Ortiz,Seung Hyub Baek,Chad M. Folkman,Rasmi R. Das,Padraic Shafer,Yanbin Chen,C. T. Nelson,Xiaoqing Pan,Ramamoorthy Ramesh,Chang-Beom Eom +10 more
TL;DR: In this paper, a multiferroic BiFeO3 has attracted great interest due to its promising application in tomagnetoelectric devices, which is comparable to those of conventional Ti-rich lead zirconia titanate, and suggested BiO3 as a strong candidate for lead-free nonvolatile memories.