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Search Publications by: Ryan Need (Assoc)

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Displaying 1 - 10 of 10

Composite Spin Hall Conductivity from Non-Collinear Antiferromagnetic Order

August 3, 2023
Author(s)
Steve Novakov, Peter B. Meisenheimer, Grace A. Pan, Patrick Kezer, Nguyen M. Vu, Alexander Grutter, Ryan F. Need, Julia Mundy, John Heron
Non-collinear antiferromagnets are an exciting new platform for studying intrinsic spin Hall effects, phenomena that arise from the materials' band structure, Berry phase curvature, and linear response to an external electric field. In contrast to

Strong Ferromagnetism Achieved via Breathing Lattices in Atomically Thin Cobaltites

January 27, 2021
Author(s)
Sisi Li, Qinghua Zhang, Shan Lin, Xiahan Sang, Ryan F. Need, Manuel A. Roldan, Wenjun Cui, Zhiyi Hu, Qiao Jin, Shuang Chen, Jiali Zhao, Jia-Ou Wang, Jiesu Wang, Meng He, Chen Ge, Can Wang, Hui-Bin Lu, Zhenping Wu, Haizhong Guo, Xin Tong, Tao Zhu, Brian Kirby, Lin Gu, Kui-juan Jin, Er-Jia Guo
Low-dimensional quantum materials that retain strong ferromagnetism down to monolayer thickness hold great potential for spintronic applications. However, ferromagnetism in the transition metal oxides decays severely when the thickness is scaled to the

Design and Realization of a Sputter Deposition System for the in situ and in operando Use in Polarized Neutron Reflectometry Experiments: Novel Capabilities

June 1, 2020
Author(s)
Jingfan Ye, Alexander Book, Sina Mayr, Henrik Gabold, Fankai Meng, Helena Schafferer, Ryan F. Need, Dustin Gilbert, Thomas Saerbeck, Jochen Stahn, Peter Boni, Wolfgang Kreuzpaintner
Recently, the design and realization of a sputter-deposition system for in situ and in operando neutron reflectometry (PNR) was reported. The device allows magnetic thin films and heterostructures to be grown, while the sample remains aligned in the

Correlating Magnetic Structure and Magnetotransport in Semimetal Thin Films of Eu 1-x Sm x TiO 3

May 15, 2020
Author(s)
Zach Porter, Ryan F. Need, Kaveh Ahadi, Yang Zhao, Zhijun Xu, Brian Kirby, Jeffrey W. Lynn, Susanne Stemmer, Stephen D. Wilson
We report on the evolution of the average and depth-dependent magnetic order in thin film samples of biaxially stressed and electron-doped EuTiO 3 for samples across a doping range 20 cm −3. Under an applied in-plane magnetic field, the G-type

Magnetic Properties and Electronic Origin of the Interface between Dilute Magnetic Semiconductors with Orthogonal Magnetic Anisotropy

May 15, 2020
Author(s)
Ryan F. Need, Seul-Ki Bac, Xinyu Liu, Sanghoon Lee, Brian Kirby, Margaret Dobrowolska, Jacek Kossut, Jacek K. Furdyna
Controlling changes in magnetic anisotropy across epitaxial film interfaces is an important prerequisite for many spintronic devices. For the canonical dilute magnetic semiconductor GaMnAs, magnetic anisotropy is highly tunable through strain and doping

Spin Seebeck Imaging of Spin-Torque Switching in Antiferromagnetic Pt/NiO Heterostructures

October 22, 2019
Author(s)
Isaiah Gray, Takahiro Moriyama, Nikhil Sivadas, Gregory M. Stiehl, John T. Heron, Ryan F. Need, Brian Kirby, David H. Low, Katja Nowack, Darrell G. Schlom, Daniel C. Ralph, Teruo Ono, Gregory D. Fuchs
We demonstrate the spin Seebeck microscope as a sensitive method for imaging in-plane antiferromagnetic order in thin films. Recently, antidamping spin-orbit torques have been used to reorient Neel order in antiferromagnetic devices. Although the readout

Using Structural Phase Transitions to Enhance the Coercivity of Ferromagnetic Films

October 17, 2019
Author(s)
Ryan F Need, Josh Lauzier, Logan Sutton, Brian J Kirby, Jose de la Venta
Storing information in magnetic recording technologies requires careful optimization of the recording media's magnetic properties. For example, heat-assisted magnetic recording (HAMR) relies on a pre-recording heating step that momentarily lowers the

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

September 6, 2018
Author(s)
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

Three-Dimensionally Structured CdS/CdTe Photovoltaics on Dual Interdigitated Back-Contacts

April 8, 2011
Author(s)
Carlos M. Hangarter, Behrang Hamadani, Ryan F. Need, Carlos R. Beauchamp, Hua Xu, John E. Bonevich, Nikolai Zhitenev, Daniel Josell
The fabrication and properties of three-dimensionally structured CdS/CdTe solar cells with back-contacts are described. Fabrication entails electrodeposition of CdS at submicrometer length scales on one of two metal electrodes interdigitated in a comb