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Search Publications by: Brian Kirby (Fed)

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Displaying 51 - 75 of 96

Lateral Magnetically Modulated Multilayers by Combining Ion Implantation and Lithography

March 1, 2017
Author(s)
Enric Menendez, Hiwa Modarresi, Claire Petermann, Josep Nogues, Neus Domingo, Haoliang Liu, Brian Kirby, Amir Syed Mohd, Zahir Salhi, Earl Babcock, Stefan Mattauch, Chris Van Haesendonck, Andre Vantomme, Kristiaan Temst
The combination of lithography and ion implantation is demonstrated to be a suitable method to prepare lateral multilayers. A laterally, compositionally and magnetically, modulated microscale patter consisting of alternating C (1.6υm-wide) and Co-CoO (2

Tailoring Exchange Couplings in Magnetic Topological Insulator/Antiferromagnet Heterostructures

January 1, 2017
Author(s)
Qing Lin He, Xufeng Kou, Alexander Grutter, Gen Yin, Lei Pan, Xiaoyu Che, Yuxiang Liu, Tianxiao Nie, Bin Zhang, Steven M.T. Disseler, Brian Kirby, William D. Ratcliff, Qiming Shao, Koichi Murata, Xiaodan Zhu, Guoqiang Yu, Yabin Fan, Mohammad Montazeri, Xiaodong Han, Julie Borchers, Kang L. Wang
Magnetic topological insulators such as Cr-doped (Bi,Sb) 2Te 3 provide a platform for the realization of versatile time-reversal symmetry-breaking physics. By constructing heterostructures with the unique Neel order in an antiferromagnetic CrSb and the

Oscillatory Non-Collinear Magnetism Induced by Interfacial Charge Transfer in Metallic Oxide Superlattices

November 22, 2016
Author(s)
Jason D. Hoffman, Brian Kirby, Jihwan Kwon, Gilberto Fabbris, John W. Freeland, Ivar Martin, Olle G. Heinonen, Paul Steadman, Hua Zhou, Christian M. Schleputz, Suzanne G. E. te Velthuis, Jian-Min Zuo, Anand Bhattacharya
Interfaces between correlated complex oxides are promising avenues to realize new forms of magnetism that arise as a result of charge transfer, proximity effects and locally broken symmetries. We report upon the discovery of a non-collinear magnetic

Concurrent Magnetic and Structural Reconstructions at the Interface of (111)-Oriented La 0.07 Sr 0.3 MnO 3 /LaFeO 3

November 21, 2016
Author(s)
I. Hallsteinsen, M. Moreau, Alexander Grutter, M. Nord, P.-E. Vullum, Dustin A. Gilbert, T. Bolstad, J. K. Grepstad, R. Holmestad, S. M. Selbach, A. T. N'Diaye, Brian Kirby, E. Arenholz, T. Tybell
We observe an induced switchable magnetic moment of 1.6 ± 0.40 υ B/Fe in the nominally antiferromagnetic LaFeOd3^/La 0.7Sr 0.3MnO 3/SrTiO 3(111). The magnetic reconstruction is driven by a mismatch of oxygen octahedra rotations resulting in an atomic

Correlation Between Morphology and Device Performance of pBTTT:PC 71 BM Solar Cells

October 1, 2016
Author(s)
Wenluan Zhang, Hao Shen, Brett W. Guralnick, Brian Kirby, Ngoc A. Nguyen, Roddel Remy, Charles Majkrzak, Michael E. Mackay
Phenyl-C 71-butyric acid methyl ester (PC 71BM) could intercalate between the side-chains of poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) creating a stable co-crystal structure, so optimal solar cell performance was obtained at

Interfacial Symmetry Control of Emergent Ferromagnetism at the Nanoscale

September 14, 2016
Author(s)
Alexander J. Grutter, A. Vailionis, Julie A. Borchers, Brian J. Kirby, C. L. Flint, C. He, E. Arenholz, Y. Suzuki
We demonstrate tunable switching between ferromagnetic and antiferromagnetic order at the CaRuO 3/CaMnO 3 interface that originates from symmetry differences in the tilt and rotation of the oxygen octahedra across the boundary. Interfaces which are

Magnetic Yoking and Tunable Interactions in FePt-Based Hard/Soft Bilayers

September 8, 2016
Author(s)
Dustin Allen Gilbert, Jung-Wei Liao, Brian J Kirby, Michael Winklhofer, Chih-Huang Lai, Kai Liu
Assessing and controlling magnetic interactions in magnetic nanostructures are critical to nanomagnetic and spintronic explorations, such as magnetic recording media, permanent magnets, magnetic memory and logic devices, etc. Here we demonstrate an

Large Energy Product Enhancement in Perpendicularly Coupled MnBi/CoFe Magnetic Bilayers

August 29, 2016
Author(s)
T. R. Gao, L. Fang, S. Fackler, S. Maruyama, X. H. Zhang, L. L. Wang, T. Rana, P. Manchanda, A. Kashyap, K. Janicka, A. L. Wysocki, A. T. N'Diaye, E. Arenholz, Julie Borchers, Brian Kirby, Brian B. Maranville, K. W. Sun, M. J. Kramer, V. P. Antropov, D. D. Johnson, R. Skomski, J. Cui, I. Takeuchi
Finding rare-earth free alternatives to Nd and Sm based permanent magnets has emerged as an urgent technological challenge due to the global economic impact of price instability of rare-earth elements. Among possible candidates, MnBi is one of the few

Measurement and Modeling of Polarized Specular Neutron Reflectivity in Large Magnetic Fields

August 1, 2016
Author(s)
Brian B. Maranville, Brian J Kirby, Alexander J Grutter, Paul Kienzle, Charles F. Majkrzak, Yaohua Liu, Cindi L. Dennis
The presence of a large applied magnetic field removes the degeneracy of the vacuum energy states for spin-up and spin-down neutrons. For polarized neutron reflectometry, this must be included in the reference potential energy of the Schrodinger equation

Structural and Magnetic Depth Profiles of Magneto-Ionic Heterostructures Beyond the Interface Limit

July 22, 2016
Author(s)
Dustin A. Gilbert, Alexander J. Grutter, Elke Arenholz, Kai Liu, Brian J. Kirby, Julie A. Borchers, Brian B. Maranville
Electric-field control of magnetism provides a promising route towards ultralow power information storage and sensor technologies. The effects of magneto-ionic motion have so far been prominently featured in the direct modification of interface chemical

Synthesis, Fabrication, and Heterostructure of Charged, Substituted Polystyrene Multilayer Dielectrics and Their Effects in Pentacene Transistors

May 10, 2016
Author(s)
Olivia J. Alley, Evan Plunkett, Tejaswini S. Kale, Xin Guo, Grace McClintock, Manasa Bhupathiraju, Brian Kirby, Daniel H. Reich, Howard E. Katz
Charge trapping and storage in polymer dielectric can be harnessed for the control of semiconductor device behavior, including organic transistors. For example, gate insulators chosen for organic transistors have an important effect on both bias stress

Controllable Positive Exchange Bias via Redox-Driven Oxygen Migration

March 21, 2016
Author(s)
Dustin A. Gilbert, Justin Olamit, Randy K. Dumas, Brian J. Kirby, Alexander J. Grutter, Brian B. Maranville, Elke Arenholz, Julie A. Borchers, Kai Liu
We have observed oxygen migration across buried interfaces in Gd^xdx^Fe 1-x/NiCoO films, which leads to tunable positive exchange bias over a relatively small cooling field range of 300 mT. The tunability is shown to be the result of an interfacial layer

Reversible Control of Magnetism in La 0.67 Sr 0.33 MnO 3 through Chemically-Induced Oxygen Migration

February 24, 2016
Author(s)
Alexander J. Grutter, Dustin A. Gilbert, U. S. Alaan, E. Arenholz, Brian B. Maranville, Julie A. Borchers, Y. Suzuki, Kai Liu, Brian J. Kirby
We demonstrate reversible control of magnetization and anisotropy in La 0.67Sr 0.33MnO 3 films through interfacial oxygen migration. Gd metal capping layers deposited onto La 0.67Sr 0.33MnO 3 leach Oxygen from the film through a solid-state redox reaction

Spatial Evolution of the Ferromagnetic Phase Transition in an Exchange Graded Film

January 29, 2016
Author(s)
Brian J. Kirby, H. F. Belliveau, D. D. Belyea, Paul A. Kienzle, Alexander J. Grutter, P. Riego, A. Berger, Casey W. Miller
A combination of experiments and numerical modeling was used to study the spacial evolution of the ferromagnetic phase transition in a thin film engineered to have a smooth gradient in exchange strength, and thus effectively a gradient in local transition

Phase Separation Enhanced Magneto-Electric Coupling in La 0.7 Ca 0.3 MnO 3 /BaTiO 3 Ultra-thin Films

December 9, 2015
Author(s)
A. Alberca, C. Munuera, Brian Kirby, N. M. Nemes, A. M. Perez-Munoz, J. Tornos, F. J. Mompean, C. Leon, J. Santamaria, M. Garcia-Hernandez
We study the origin of the magnetoelectric coupling in manganite films on ferroelectric substrates. We find large magnetoelectric coupling in La 0.7Ca 0.3MnO 3/BaTiO 3 ultra-thin films in experiments based on the converse magnetoelectric effect. The

Realization of Ground-State Artificial Skyrmion Lattices at Room Temperature

October 8, 2015
Author(s)
Dustin A. Gilbert, Brian B. Maranville, Andy L. Balk, Brian J. Kirby, Peter Fischer, Daniel T. Pierce, John Unguris, Julie A. Borchers, Kai Liu
The topological nature of magnetic skyrmions deriving from broken symmetries leads to extraordinary static and dynamic properties that provide new insight in fundamental problems of magnetism and exciting potentials for exploitation in novel magnetic

Proximity-Driven Enhanced Magnetic Order at Ferromagnetic-Insulator-Magnetic-Topological Insulator Interface

August 17, 2015
Author(s)
Mingda Li, Cui-Zu Chang, Brian Kirby, Michelle E. Jamer, Wenping Cui, Lijun Wu, Peng Wei, Yimei Zhu, Don Heiman, Ju Li, Jagadeesh S. Moodera
Magnetic exchange driven proximity effect at a magnetic insulator/topological insulator (MI/TI) interface provides a rich playground for novel phenomena as well as a way to realize low energy dissipation quantum devices. Here we report a dramatic

Electric Field Control of Interfacial Ferromagnetism in CaMnO 3 /CaRuO 3 Heterostructures

July 24, 2015
Author(s)
Alexander J. Grutter, Brian J. Kirby, M. T. Gray, C. L. Flint, U. S. Alaan, Y. Suzuki, Julie A. Borchers
A key milestone for the development of low-power spintronic devices is electric field control of ferromagnetism. To that end, we have probed the electric field dependence of the emergent ferromagntic layer at CaRuO 3/CaMnO 3 interfaces in bilayers

Effective Anisotropy Gradient in Pressure Graded [Co/Pd] Multilayers

February 14, 2015
Author(s)
Brian J. Kirby, P. K. Greene, Brian B. Maranville, J. E. Davis, Kai Liu
A vertically graded anisotropy profile has been proposed as an optimized balance of low coercivity and thermal stability for multilayers used in magnetic media. Deposition pressure is known to have a profound effect on the magnetic reversal properties of

Interfacial Exchange Coupling in Fe/(Ga,Mn)As Bilayers

June 16, 2014
Author(s)
A. M. Alsmadi, Y. Choi, D.J. Keavney, K.F. Eid, Brian Kirby, X. Liu, J. Leiner, K. Tivakornsasithorn, M. Dobrowolska, J. K. Furdyna
We have carried out a systematical study of magnetic order and magnetic interlayer coupling in Fe/(Ga,Mn)As bilayers using superconducting quantum interference device magnetometry, polarized neutron reflectometry, element-specific x-ray absorption

Effect of Interfacial Octahedral Behavior in Ultrathin Manganite Films

May 14, 2014
Author(s)
E. J. Moon, P. V. Balachandran, Brian Kirby, D.J. Keavney, R.J. Sichel-Tissot, C. M. Schleputz, E. Karapetrova, X. M. Cheng, James M. Rondinelli, S. J. May
We investigate structural coupling of the MnO 6 octahedra across a film/substrate interface and the resultant changes of the physical properties of ultrathin La 2/3}Sr 1/3}MnO 3 (LSMO) films. In order to isolate the effect of interfacial MnO 6 octahedral

Structural and Magnetic Etch Damage in CoFeB

May 7, 2014
Author(s)
L. Krayer, June W. Lau, Brian Kirby
A detailed understanding of the interfacial properties of think films used in magnetic media is critical for the aggressive component scaling required for continued improvement in storage density. In particular, it is important to understand how common

Deposition Order Dependent Magnetization Reversal of Pressure Graded Co/Pd Films

April 15, 2014
Author(s)
P. K. Greene, Brian Kirby, June W. Lau, Julie Borchers, M .R. Fitzsimmons, Kai Liu
Magnetization reversal mechanisms have been investigated in pressure graded Co/Pd multilayer thin films with inverted deposition orders. Structural and magnetic properties have been investigated using x-ray diffraction, transmission electron microscopy

Interdependence Between Training and Magnetization Reversal in Granular Co-CoO Exchange Bias Systems

April 9, 2014
Author(s)
E. Menendez, T. Dias, J. Geshev, J. F. Lopez-Barbera, J. Nogues, R. Steitz, Brian Kirby, Julie Borchers, L.M.C. Pereira, A. Vantomme, K. Temst
The interdependence between training and magnetization reversal in granular Co-CoO exchange bias systems prepared by O ion implantation in Co thin films is demonstrated by polarized neutron reflectometry. The implantations result in rather uniform O depth