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Search Publications by Alexander Grutter

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Displaying 1 - 25 of 41

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

June 15, 2020
Yabin Fan, Patrick A. Quarterman, Joseph Finley, Jiahao Han, Pengxiang Zhang, Justin T. Hou, Mark D. Stiles, Alexander J 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

Charge Carrier Transport with Low-Temperature Anomalies in Engineered 4d5 Oxide Superlattices of (Sr 2 IrO 4 ) 4 /(Sr 3 Ru 2 O 27 ) N

April 30, 2020
Hui Xu, Alexander J Grutter, Zhangzhang Cui, Zhicheng Wang, Xiaofang Zhai, Yalin Lu
We report tunable conduction behavior of a series of (Sr2IrO4)4/(Sr3Ru2O27)N (N=1, 2, 4) atomic layer superlattices, in which itinerant electron, itinerant hole and localized electron transports can be varied dependent on the period. Furthermore, we find a

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

April 10, 2020
Zhangzhang Cui, Alexander J Grutter, Hua Zhou, Hui Cao, Yongqi Dong, Dustin Allen Gilbert, Jingyuan Wang, Yi-Sheng Liu, Jiaji Ma, Zhenpeng Hu, Jinghua Guo, Jing Xia, Brian J 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 J Grutter, Brian J 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 J 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 A. Quarterman, Alexander J Grutter, Brian J Kirby, Julie A. 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 J 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 J 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 J Grutter, Brian J 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 J Grutter, Chih-Yeh Huang, Aubrey Penn, Navid Mottaghi, Saeed Yousefi, Allison Haertter, Shalini Kumari, James LeBeau, Brian J 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 Allen Gilbert, M. Belmeguenai, J. Vogel, S. Pizzini, E. Martinez, A. Lamperti, J. B. Mohammedi, A. Laborieux, Y. Roussigne, Alexander J Grutter, E. Arenholtz, Patrick A. 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 J 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 J. 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 J. Grutter, Yawen Liu, Guoqiang Yu, Chao-Yao Yang, Dustin Allen Gilbert, Elke Arenholz, Padraic Shafer, Xiaoyu Chi, Chi Tang, Mohammed Aldosary, Aryan Navabi, Qing Lin He, Brian J. 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

Phonon Localization in Heat Conduction

December 21, 2018
M. N. Luckyanova, J. Mendoza, H. Lu, B. Song, S. Huang, J. Zhou, M. Li., Y. Dong, H. Zhou, J. Garlow, L. Wu, Brian J Kirby, Alexander J Grutter, Alex A. Puretzky, Y. Zhu, M. S. Dresselhaus, A. Gossard, G. Chen
We report localization-like behavior in phonon heat conduction observed both in measurement of the thermal conductivities of GaAs/AlAs superlattice (SL) thin films with interfacial disorder caused by ErAs nanodots randomly distributed at the interfaces

Helical Magnetism in Sr-Doped CaMn 7 O 12 Films

December 19, 2018
Amanda Huon, Anuradha M. Vibhakar, Alexander J Grutter, Julie A. Borchers, Steven Disseler, Yaohua Liu, Wei Tian, Fabio Orlandi, Pascal Manuel, Dmitry D. Khalyavin, Yogesh Sharma, Andreas Herklotz, Ho Nyung Lee, Michael R. Fitzsimmons, Roger D. Johnson, Steven J. May
Noncollinear magnetism can play an important role in multiferroic materials but is relatively understudied in oxide heterostructures compared to their bulk counterparts. Using magnetometry and neutron diffraction, we demonstrate the presence of helical

Long-Range Electric Field Control of Permalloy Layers in Strain-Coupled Composite Multiferroics

October 18, 2018
Michelle Elizabeth Jamer, Colin R. Rementer, Anthony Barra, Alexander J Grutter, Kevin Fitzell, Daniel Bernard Gopman, Julie A. Borchers, Gregory P. Carman, Brian J Kirby, Jane P. Chang
Artificial composite multiferroic materials can be created by interfacing magnetostrictive and piezoelectric materials, allowing for electric field control of magnetic properties. For multilayer device applications, addition of weakly magnetostrictive

Ionic Tuning of Cobaltites at the Nanoscale

October 3, 2018
Dustin Allen Gilbert, Alexander J Grutter, Peyton D. Murray, Rajesh V. Chopdekar, Alexander M. Kane, Aleksey L. Ionin, Michael S. Lee, Steven R. Spurgeon, Brian J Kirby, Brian B. Maranville, Alpha T. N'Diaye, Apurva Mehta, Elke Arenholz, Kai Liu, Yayoi Takamura, Julie A. Borchers

Resolving Interfacial Charge Transfer in Titanate Superlattices using Resonant X-Ray Reflectometry

September 6, 2018
Ryan F. Need, P. B. Marshall, E. Weschke, Alexander J. Grutter, Dustin Allen Gilbert, E. Arenholz, P. Shafer, S. Stemmer, Stephen D. Wilson
Oxide interfaces, where strong electron-electron correlations lead to emergent phase behavior, have been the subject of intense study in recent years. However, the buried nature of heterointerfaces often makes them challenging to probe directly. Addressing

Strain-Induced Competition between Ferromagnetism and Emergent Antiferromagnetism in (Eu,Sr)MnO 3

September 4, 2018
Alexander J Grutter, Steven M. Disseler, E. J. Moon, Dustin Allen Gilbert, E. Arenholz, A. Suter, T. Prokscha, Z. Salman, Brian J Kirby, S. J. May
We demonstrate emergent antiferromagnetic interactions is strained thin films of the mixed valence manganite (Eu,SR)MnO3. Although the composition studied, Eu0.7Sr0.3MnO3, will nominally yield a ferromagnetic phase in bulk, we observe significant

Topological Transitions Induced by Antiferromagnetism in a Thin-Film Topological Insulator

August 29, 2018
Qing Lin He, Gen Yin, Luyan Yu, Alexander J Grutter, Lei Pan, Chui-Zhen Chen, Xiaoyu Che, Guoqiang Yu, Bin Zhang, Qiming Shao, Alexander L. Stern, Brian Casas, Jing Xia, Xiaodong Han, Brian J Kirby, Roger K. Lake, K. T. Law, Kang L. Wang
Ferromagnetism in topological insulators (TIs) opens a topologically non-trivial exchange band gap, providing an exciting platform for manipulating the topological order through external magnetic field. Here, we experimentally show that the surface of an