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Search Publications by

Alexander Grutter (Fed)

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Displaying 1 - 25 of 51

Elucidating Proximity Magnetism through Polarized Neutron Reflectometry and Machine Learning

October 29, 2021
Nina Andrejevic, Zhantao Chen, Thanh Nguyen, Leon Fan, Henry Heiberger, Valeria Lauter, Ling-Jie Zhou, Yi-Fan Zhao, Cui-Zu Chang, Alexander Grutter, Mingda Li
Polarized neutron reflectometry (PNR) is a powerful technique to interrogate the structures of multilayered magnetic materials with depth sensitivity and nanometer resolution. However, reflectometry profiles often inhabit a complicated objective function

Antiferromagnetic VdW Phase at the Interface of Sputtered Topological Insulator/Ferromagnet Bi 2 Te 3 /Ni 80 Fe 2 0 Heterostructures

October 28, 2021
Nirjhar Bhattacharjee, Krishnamurthy Mahalingam, Adrian Fedorko, Valeria Lauter, Matthew Matzelle, Bahadur Singh, Alexander Grutter, Alexandria Will-Cole, Michael Page, Michael McConney, Robert Markiewicz, Arun Bansil, Don Heiman, Nian Sun
Magnetic ordering in topological insulators (TI) is crucial for breaking time-reversal symmetry (TRS) and thereby opening a gap in the topological surface states (TSSs) [1-6], which is the key for realizing useful topological properties such as the quantum

Magnetic Field-Induced Non-Trivial Electronic Topology in Fe 3-x GeTe 2

October 7, 2021
Juan Macy, Danilo Ratkovski, Purnima P. Balakrishnan, Mara Strungaru, Yu-Che Chiu, Aikaterini Flessa, Alex Moon, Wenkai Zheng, Ashley Weiland, Gregory T. McCandless, Julia Y. Chan, Govind S. Kumar, Michael Shatruk, Alexander Grutter, Julie Borchers, William D. Ratcliff, Eun S. Choi, Elton J. Santos, Luis Balicas
The anomalous Hall, Nernst and thermal Hall coefficients of the itinerant ferromagnet Fe3−xGeTe2 display several features upon cooling, like a reversal in the Nernst signal below T = 50 K pointing to a topological transition possibly associated to the

Electrically Driven Exchange Bias via Solid State Magneto-Ionics

August 9, 2021
Peyton Murray, Alexander Grutter, Brian Kirby
Electrically induced ionic motion offers a new way to realize voltage-controlled magnetism, opening the door to a new generation of logic, sensor, and data storage technologies. Here, we demonstrate an effective approach to magneto-ionically and

Resonant Spin Transmission Mediated by Magnons in a Magnetic Insulator Multilayer Structure

June 3, 2021
Yabin Fan, Joseph Finley, Jiahao Han, Megan E. Holtz, Patrick Quarterman, Pengxiang Zhang, Taqiyyah S. Safi, Justin T. Hou, Alexander Grutter, Luqiao Liu
One important goal of magnonics is to discover novel wave properties of magnons, which are quanta of collective excitation in magnets, to make it compatible for application on coherent information transmission and processing1,2. However, thin-film

Exchange Bias Switching in an Antiferromagnet/Ferromagnet Bilayer Driven by Spin-Orbit Torque

December 1, 2020
Shouzhong Peng, Daoqian Zhu, Weixiang Li, Hao Wu, Alexander Grutter, Dustin A. Gilbert, Jiaqi Lu, Danrong Xiong, Wenlong Cai, Padraic Shafer, Kang L. Wang, Weisheng Zhao
Electrical manipulation of exchange bias and magnetization in antiferromagnet/ferromagnet thin films has been of great interest in recent years. Here, we experimentally demonstrate current-induced switching of exchange bias in perpendicularly magnetized

Large Exchange Splitting in Monolayer Graphene Magnetized by an Antiferromagnet

October 1, 2020
Yingying Wu, Gen Yin, Lei Pan, Alexander Grutter, Quanjun Pan, Albert Lee, Dustin A. Gilbert, Julie Borchers, William D. Ratcliff, Ang Li, Xiao-dong Han, Kang L. Wang
Spin splitting in graphene has been identified as a key component for unlocking multifunctionality with low dissipation and long-distance spin transport. Magnetic proximity effects are an extremely promising route to realizing exchange splitting in

Observation of Quantum Anomalous Hall Effect and Exchange Interaction in Topological Insulator/Antiferromagnet Heterostructure

August 27, 2020
Lei Pan, Alexander Grutter, Peng Zhang, Xiaoyu Che, Tomohiro Nozaki, Alex Stern, Mike Street, Bing Zhang, Brian Casas, Qing L. He, Eun S. Choi, Steven M. Disseler, Dustin Gilbert, Gen Yin, Qiming Shao, Peng Deng, Yingying Wu, Xiaoyang Liu, Xufeng Kou, Sahashi Masashi, Xiaodong Han, Christian Binek, Scott Chambers, Jing Xia, Kang L. Wang
Integration of a quantum anomalous Hall insulator with a magnetically ordered material provides an additional degree of freedom through which we may control the resulting exotic quantum states. Here, we report an experimental observation of the quantum

Termination Switching of Antiferromagnetic Proximity Effect in Topological Insulator

August 12, 2020
Chao-Yao Yang, Lei Pan, Alexander Grutter, Haiying Wang, Xiaoyu Che, Qing L. He, Yingying Wu, Dustin A. Gilbert, Padraic Shafer, Elke Arenholz, Hao Wu, Gen Yin, Peng Deng, Julie Borchers, William D. Ratcliff, Kang L. Wang
The magnetic proximity effect (MPE) allows exchange-coupling of topological insulators (TIs) with magnetically ordered materials to break time-reversal-symmetry and open a gap in the Dirac-cone surface state, with the goal of realizing quantum anomalous

Differentiation between Strain and Charge Mediated Magnetoelectric Coupling in La 0.7 Sr 0.3 MnO 3 /Pb(Mg 1/3 Nb 2/3) d0.7^Ti 0.3 O 3 (001)

June 17, 2020
T. Bhatnagar-Schoffmann, E. Kentzinger, A. Sarkar, P. Schoffmann, Q. Lan, L. Jin, A. Kovacs, Alexander Grutter, Brian Kirby, R. Beerwerth, M. Waschk, A. Stellhorn, U. Rucker, R. E. Dunin-Borkowski, Th. Bruckel
Magnetoelectric (ME) coupling in La0.7Sr0.3MnO3/Pb(Mg1/3Nb2/3)d0.7^Ti0.3O3 (LSMO/PMN-PT (001)) has been probed in the past years to identify the underlying mechanism behind it. PMN-PT, which is well known for its excellent piezoelectric properties, also

Manipulation of Coupling and Magnon Transport in Magnetic Metal-Insulator Hybrid Structures

June 15, 2020
Yabin Fan, Patrick Quarterman, Joseph Finley, Jiahao Han, Pengxiang Zhang, Justin T. Hou, Mark D. Stiles, Alexander Grutter, Luqiao Liu
Ferromagnetic metals and insulators are widely used for generation, control and detection of magnon spin signals. Most magnonic structures are based primarily on either magnetic insulators or ferromagnetic metals, while heterostructures integrating both of

Correlation-Driven Eightfold Magnetic Anisotropy in a Two-Dimensional Oxide Monolayer

April 10, 2020
Zhangzhang Cui, Alexander Grutter, Hua Zhou, Hui Cao, Yongqi Dong, Dustin A. Gilbert, Jingyuan Wang, Yi-Sheng Liu, Jiaji Ma, Zhenpeng Hu, Jinghua Guo, Jing Xia, Brian Kirby, Padraic Shafer, Elke Arenholz, Hanghui Chen, Xiaofang Zhai, Yalin Lu
Engineering magnetic anisotropy (MA) in two-dimensional (2D) ferromagnetic materials has enormous scientific and technological implications. The uniaxial anisotropy universally exhibited by 2D ferromagnetic materials has only two stable spin directions

Strain-Induced Majority Carrier Inversion in Ferromagnetic Epitaxial LaCoO^d3-d Thin Films

March 4, 2020
Vipul Chaturvedi, Jeff Walter, Arpita Paul, Alexander Grutter, Brian Kirby, Jong Seok Jeong, Hua Zhou, Zhan Zhang, Biqiong Yu, Martin Greven, K. Andre Mkhoyan, Turan Birol, Chris Leighton
Tensile-strained LaCoO3-δ thin films are ferromagnetic, in sharp contrast to the zero-spin bulk, although no clear consensus has emerged as to the origin of this phenomenon. While magnetism has been heavily studied, relatively little attention has been

Emergent Electric Field Control of Phase Transformation in Oxide Superlattices

February 1, 2020
Di Yi, Yujia Wang, Olaf M. J. van t'Erve, Liubin Xu, Hongtao Yuan, Michael J. Veit, Purnima P. Balakrishnan, Yongseong Choi, Alpha T. N'Diaye, Padraic Shafer, E. Arenholz, Alexander Grutter, Haixuan Xu, Pu Yu, Berend T. Jonker, Yuri Suzuki
Electric fields have been shown to transform materials with respect to their structure and properties, thus enabling many applications ranging from batteries to spintronics. Recently electrolytic gating, which can generate large electric fields and voltage

Dysprosium Iron Garnet Thin Films with Perpendicular Magnetic Anisotropy on Silicon

January 1, 2020
Jackson J. Bauer, Ethan R. Rosenberg, Subhajit Kundu, K. Andre Mkhoyan, Patrick Quarterman, Alexander Grutter, Brian Kirby, Julie Borchers, Caroline A. Ross
Magnetic insulators, such as the rare-earth iron garnets, are promising materials for energy-efficient spintronic memory and logic devices, and their anisotropy, magnetization and other properties can be tuned over a wide range through selection of the

Damping Enhancement in Coherent Ferrite-Insulating-Paramagnet Bilayers

November 19, 2019
Jacob J. Wisser, Alexander Grutter, Dustin A. Gilbert, Alpha T. N'Diaye, Christoph Klewe, Padraic Shafer, Elke Arenholz, Yuri Suzuki, Satoru Emori
High-quality epitaxial ferrites, such as low-damping MgAl-ferrite (MAFO), are promising nanosclae building blocks for all-oxide heterostructures driven by pure spin current. However, the impact of oxide interfaces on spin dynamics in such heterostructures

Tunable Magnetic Ordering through Cation Selection in Entropic Spinel Oxides

October 21, 2019
Brianna Musico, Quinton Wright, T. Zac Ward, Alexander Grutter, Elke Arenholz, Dustin Gilbert, David Mandrus, Veerle Keppens
Twelve multicomponent spinels, comprised of (Mg, Cr, Mn, Co, Fe, Ni, Cu, and/or Zn)(Cr, Fe or Al)2O4, were prepared using solid state synthesis methods, resulting in nine homogenous, single phase samples with a Fm-3m structure, and three samples with

Ultrathin Interfacial Layer with Suppressed Room Temperature Magnetization in Magnesium Aluminum Ferrite Thin Films

September 24, 2019
Jacob J. Wisser, Satoru Emori, Lauren Riddiford, Aaron Altman, Peng Li, Krishnamurthy Mahalingam, Brittany T. Urwin, Brandon M. Howe, Michael R. Page, Alexander Grutter, Brian Kirby, Yuri Suzuki
Low-damping magnetic oxide thin films with small thicknesses are essential for efficient insulator spintronic devices, particularly those driven by spin torques effects. Here, we investigate depth-resolved compositional and magnetic properties of epitaxial

Effect of Oxygen Stoichiometry on the Magnetization Profiles and Negative Magnetization in LSMO Thin Films

September 14, 2019
Robbyn Trappen, Alexander Grutter, Chih-Yeh Huang, Aubrey Penn, Navid Mottaghi, Saeed Yousefi, Allison Haertter, Shalini Kumari, James LeBeau, Brian Kirby, Mikel B. Holcomb
The depth dependent magnetization in thin film oxygen stoichiometric and oxygen deficient La0.7Sr0.3MnO3 is investigated by using polarized neutron reflectivity. The stoichiometric sample shows enhanced interfacial magnetization relative to the rest of the

NonVolatile Ionic Modification of the Dzyaloshinskii-Moriya Interaction

September 4, 2019
L. Herrera Diez, Y. T. Liu, Dustin A. Gilbert, M. Belmeguenai, J. Vogel, S. Pizzini, E. Martinez, A. Lamperti, J. B. Mohammedi, A. Laborieux, Y. Roussigne, Alexander Grutter, E. Arenholtz, Patrick Quarterman, Brian B. Maranville, S. Ono, M. Salah El Hadri, R. Tolley, E. E. Fullerton, L. Sanchez-Tejerina, A. Stashkevich, S. M. Cherif, A. D. Kent, D. Querlioz, J. Langer, B. Ocker, D. Ravelosona
The possibility to tune the Dzyaloshinskii Moriya interaction (DMI) by electric (E) field gating in ultra-thin magnetic materials has opened new perspectives in terms of controlling the stabilization of chiral spin structures. Most recent efforts have used

X-Ray Nanodiffraction Studies of Ionically Controlled Nanoscale Phase Separation in Cobaltites

August 5, 2019
Geoffery Rippy, Lacey Trinh, Alexander M. Kane, Aleksey L. Ionin, Michael S. Lee, Rajesh V. Chopdekar, Joyce M. Christiansen-Salameh, Dustin A. Gilbert, Alexander Grutter, Peyton D. Murray, Martin V. Holt, Zhonghou Cai, Kai Liu, Yayoi Takamura, Roopali Kukreja
Complex oxide heterostructures provide access to emergent functional and structural phases which are not present in the bulk constituent materials. In this letter, we focus on Gd/La0.67Sr0.33CoO3 (LSCO) heterostructures due to the high oxygen ion

Effects of Field Annealing on MnN/CoFeB Exchange Bias Systems

June 24, 2019
Patrick A Quarterman, I. Hallsteinsen, M. Dunz, M. Meinert, E. Arenholz, Julie A. Borchers, Alexander J. Grutter
We report the effects of nitrogen diffusion on exchange bias in MnN/CoFeB heterostructures as a function of MnN thickness and field annealing temperature. We find that competing effects occur in which high-temperature annealing enhances exchange bias in

Electron Doping BaZrO 3 via Topochemical Reduction

June 19, 2019
Thomas Orvis, Mythili Surendran, Yang Liu, Shanyuan Niu, Shinichiro Muramoto, Alexander Grutter, Jayakanth Ravichandran
We report the topochemical reduction of epitaxial thin films of the cubic perovskite BaZrO3. Reduction with calcium hydride yields n-type conductivity in the films, despite the wide bandgap and low electron affinity of the parent material. X-ray

Exploring Interfacial Exchange Coupling and Sublattice Effect in Heavy Metal/Ferrimagnetic Insulator Heterostructures using Hall Measurements, X-Ray Magnetic Circular Dichroism, and Neutron Reflectometry

March 4, 2019
Qiming Shao, Alexander Grutter, Yawen Liu, Guoqiang Yu, Chao-Yao Yang, Dustin A. Gilbert, Elke Arenholz, Padraic Shafer, Xiaoyu Chi, Chi Tang, Mohammed Aldosary, Aryan Navabi, Qing Lin He, Brian Kirby, Jing Shi, Kang L. Wang
Ferrimagnetic insulators (FMIs), such as rare-earth iron garnets, are of considerable interest for low-power spintronics due to low Gilbert damping and the absence of free charge carriers. FMIs are also promising candidate materials for high-frequency