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Search Publications by Alexander Grutter

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Displaying 26 - 41 of 41

Exchange-Biasing Topological Charges by Antiferromagnetism

July 17, 2018
Qing Lin He, Gen Yin, Alexander J Grutter, Lei Pan, Xiaoyu Che, Guoqiang Yu, Dustin Allen Gilbert, Steven M. Disseler, Yizhou Liu, Padraic Shafer, Bin Zhang, Yingying Wu, Brian J Kirby, Elke Arenholz, Roger K. Lake, Xiaodong Han, Kang L. Wang, Xiaodong Han, Kang L. Wang
'Geometric' or 'topological' Hall effect is induced by the emergent gauge field experienced by the carriers adiabatically passing through chiral spin textures. This effect is an indication of non-trivial spin textures, such as magnetic skyrmions. Here we

Ion-Gel-Gating-Induced Oxygen Vacancy Formation in Epitaxial La 0.5Sr d0.5^CoO^d3-d Films from in operando X-ray and Neutron Scattering

December 19, 2017
Jeff Walter, Guichuan Yu, Biqiong Yu, Alexander J Grutter, Brian J Kirby, Julie A. Borchers, Zhan Zhang, Hua Zhou, Turan Birol, Martin Greven, Chris Leighton
Ionic-liquid/gel-based transistors have emerged as an ideal means to accumulate high charge carrier densities at the surfaces of materials such as oxides, enabling control over electronic phase transitions. Substantial gaps remain in the understanding of

Complex Three-Dimensional Magnetic Ordering in Segmented Nanowire Arrays

July 12, 2017
Alexander J Grutter, Kathryn Krycka, Elena V. Tartakovskaya, Julie A. Borchers, K. Sai Madhukar Reddy, Eduardo Ortega, Arturo Ponce, Bethanie J. H. Stadler
The first comprehensive three-dimensional picture of magnetic ordering in high-density arrays of segmented FeGa/Cu nanowires is experimentally realized through the application of Polaris small angle neutron scattering. The competing energetics of dipolar

Compensated Ferrimagnetism in the Zero-Moment Heusler Alloy Mn 3 Al

June 30, 2017
Michelle Elizabeth Jamer, Yung Jui Wang, Gregory M. Stephen, Ian J. McDonald, Alexander J Grutter, George E. Sterbinsky, Dario A. Arena, Julie A. Borchers, Brian J Kirby, Laura H. Lewis, Bernardo Barbiellini, Arun Bansil, Don Heiman
While antiferromagnets have been proposed as components to limit stray magnetic fields in spintronics devices, their inability to be spin polarized inhibits their use. Compensated ferrimagnets are a unique solution to this dilemma since they have zero net

Tailoring Exchange Couplings in Magnetic Topological Insulator/Antiferromagnet Heterostructures

January 1, 2017
Qing Lin He, Xufeng Kou, Alexander J Grutter, Gen Yin, Lei Pan, Xiaoyu Che, Yuxiang Liu, Tianxiao Nie, Bin Zhang, Steven M.T. Disseler, Brian J Kirby, William D. Ratcliff, Qiming Shao, Koichi Murata, Xiaodan Zhu, Guoqiang Yu, Yabin Fan, Mohammad Montazeri, Xiaodong Han, Julie A. Borchers, Kang L. Wang
Magnetic topological insulators such as Cr-doped (Bi,Sb)2Te3 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

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

November 21, 2016
I. Hallsteinsen, M. Moreau, Alexander J Grutter, M. Nord, P.-E. Vullum, Dustin Allen Gilbert, T. Bolstad, J. K. Grepstad, R. Holmestad, S. M. Selbach, A. T. N'Diaye, Brian J Kirby, E. Arenholz, T. Tybell
We observe an induced switchable magnetic moment of 1.6 ± 0.40 υB/Fe in the nominally antiferromagnetic LaFeOd3^/La0.7Sr0.3MnO3/SrTiO3(111). The magnetic reconstruction is driven by a mismatch of oxygen octahedra rotations resulting in an atomic

Interfacial Symmetry Control of Emergent Ferromagnetism at the Nanoscale

September 14, 2016
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 CaRuO3/CaMnO3 interface that originates from symmetry differences in the tilt and rotation of the oxygen octahedra across the boundary. Interfaces which are symmetry

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

August 1, 2016
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
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

Controllable Positive Exchange Bias via Redox-Driven Oxygen Migration

March 21, 2016
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^Fe1-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 of

Perspective: Probing 2-D Magnetic Structures in a 3-D World

March 1, 2016
Alexander J. Grutter
Magnetic interfaces have been identified as promising systems upon which to base next-generation spintronic devices. In these nearly two-dimensional systems, deviations from bulk electronic structure and competition between nearly degenerate magnetic

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

February 24, 2016
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 La0.67Sr0.33MnO3 films through interfacial oxygen migration. Gd metal capping layers deposited onto La0.67Sr0.33MnO3 leach Oxygen from the film through a solid-state redox reaction to

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

January 29, 2016
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

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

July 24, 2015
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 CaRuO3/CaMnO3 interfaces in bilayers fabricated