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Search Publications by: William D. Ratcliff (Fed)

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Displaying 1 - 25 of 52

Effects of Dimensionality on the Electronic Structure of Ruddlesden-Popper Chromates Srn+1CrnO3n+1

July 18, 2024
Author(s)
Spencer Doyle, Lerato Takana, Margaret Anderson, Dan Segedin, Hesham El-Sherif, Charles Brooks, Xiaoping Wang, Padraic Shafer, Alpha N'Diaye, Ismail El Baggari, William Ratcliff, Andres Cano, Quintin Meier, Julia Mundy
Transition-metal oxides host a wide variety of electronic phenomena that can be significantly influenced by the effective dimensionality of the system under consideration. These include charge, spin, and orbital orderings, as well as unconventional

Topological Hall effect induced by chiral fluctuations in a kagome lattice

January 30, 2024
Author(s)
Kyle Fruhling, Alenna Streeter, Sougata Mardanya, Xiaoping Wang, Priya Baral, Oksana Zaharko, Igor Mazin, Sugata Chowdhury, William Ratcliff, Fazel Tafti
Topological Hall effect (THE) is a hallmark of scalar spin chirality, which is found in static skyrmion lattices. Recent theoretical works have shown that scalar spin chirality could also emerge dynamically from thermal spin fluctuations. Evidence of such

Antiferromagnetic Metal Phase in an Electron-Doped Rare-Earth Nickelate

April 1, 2023
Author(s)
Qi Song, Spencer Doyle, Grace Pan, Ismail El Baggari, Dan Segedin, Denisse Cordova Carrizales, Johanna Nordlander, Christian Tzschaschel, James Ehrets, Zubia Hasan, Hesham El-Sherif, Jyoti Krishna, Chase Hanson, Harrison LaBollita, Aaron Bostwick, Chris Jozwiak, Eli Rotenberg, Su-Yang Xu, Alessandra Lanzara, Alpha N'Diaye, Colin Heikes, Yaohua Liu, Hanjong Paik, Charles Brooks, Betul Pamuk, John Heron, Padraic Shafer, William D. Ratcliff, Antia Botana, Luca Moreschini, Julia A. Mundy
Long viewed as passive elements, antiferromagnetic materials emerged as promising candidates for spintronic devices due to their insensitivity to external fields and potential for high-speed switching. Recent work in spin orbitronics has identified ways to

Unravelled and Glassy Magnetism in PbFe 1/2 Nb 1/2 O 3 - (2) Neutron Scattering

October 11, 2022
Author(s)
C. Stock, B. Roessli, Peter M. Gehring, Jose Rodriguez Rivera, N. Giles-Donovan, S. Cochran, Guangyong Xu, P. Manuel, M. J. Gutmann, William D. Ratcliff, T. Fennell, Y. Su, X. Li, H. Luo
We apply neutron scattering to investigate the magnetism in the relaxor ferroelectric PbFe 1/2Nb 1/2O 3 (PFN). Similar to the lack of spatially long-range ferroelectric order in prototypical relaxors like Pb(Mg,Zn) 1/3Nb 2/3O 3 (PMN and PZN), spatially

Revealing the Symmetry of Materials through Neutron Diffraction

June 12, 2022
Author(s)
William D. Ratcliff
Magnetic materials are used in many devices in everyday life. To control their properties, we must first understand how they are ordered. This can be accomplished through neutron diffraction measurements. However, in many cases, there are too many

A Semi-Supervised Approach for Automatic Crystal Structure Classification

November 1, 2021
Author(s)
Satvik Lolla, Haotong Liang, A. Gilad Kusne, Ichiro Takeuchi, William D. Ratcliff
The structural solution problem can be a daunting and time consuming task. Especially in the presence of impurity phases, current methods such as indexing become more unstable. In this work, we apply the novel approach of semi-supervised learning towards

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

October 7, 2021
Author(s)
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 Fe 3−xGeTe 2 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

Magnetic Ordering and Structural Distortion in PrFeAsO Single Crystal Studied by Neutron and X-ray Scattering

May 5, 2021
Author(s)
M. G. Kim, William D. Ratcliff, D. M. Pajerowski, J.-W. Kim, J.-Q. Yan, Jeffrey W. Lynn, A. I. Goldman, A. Kreyssig
We report the magnetic ordering and structural distortion in PrFeAsO crystals, the basis compound for one of the oxypnictide superconductors, using high-resolution x-ray diffraction, neutron diffraction, and x-ray resonant magnetic scattering (XRMS). We

Control of Magnetoelectric Coupling in the Co 2 Y-Type Hexaferrites

March 16, 2021
Author(s)
Chang B. Park, Kwang W. Shin, Sae H. Chun, Jun H. Lee, Yoon S. Oh, Steven M. Disseler, Colin A. Heikes, William D. Ratcliff, Woo-Suk Noh, Jae-Hoon Park, Kee H. Kim
We comprehensively investigated the magnetic, ferroelectric, and ME properties of Ba 2-xSr xCo 2(Fe 1-yAl y) 12O 22 single crystals in broad doping ranges of Sr (1.0 less than or equal to} x less than or equal to} 1.8) and Al (0.00 less than or equal to} y

Kitaev Interactions in the Co Honeycomb Antiferromagnets Na 3 Co 2 SbO 6 and Na 2 Co 2 TeO 6

December 24, 2020
Author(s)
M. Songvilay, J. Robert, Jose Rodriguez Rivera, William D. Ratcliff, F. Damay, V. Baledent, M. Jimenez-Ruiz, P. Lejay, E. Pachoud, A. Hadj-Azzem, V. Simonet, C. Stock
Co 2+ ions in an octahedral crystal field, stabilize a jeff = 1⁄2 ground state with an orbital degree of freedom and and have been recently put forward for realising Kitaev interactions, a prediction that we have tested by investigating spin dynamics in

Evolution of the Magnetic Properties in the Antiferromagnet Ce 2 RhIn 8 Simultaneously Doped with Cd and Ir

November 20, 2020
Author(s)
D. S. Christovam, G. S. Freitas, M. M. Piva, J. C. Souza, M. O. Malcolms, O. L. Canton, Juscelino Leao, William D. Ratcliff, Jeffrey W. Lynn, C. Adriano, P. G. Pagliuso
We report the evolution of the magnetic properties of Ce 2Rh 1−xIr xIn 8−yCd y single crystals. In particular, for Ce 2Rh 0.5Ir 0.5In 8 (T N = 2.0 K) and Ce 2Rh 0.5Ir 0.5In 7.79Cd 0.21 (T N = 4.2 K), we have solved the magnetic structure of these compounds

Large Exchange Splitting in Monolayer Graphene Magnetized by an Antiferromagnet

September 30, 2020
Author(s)
Yingying Wu, Gen Yin, Lei Pan, Alexander Grutter, Quanjun Pan, Albert Lee, Dustin A. Gilbert, Julie A. 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

Termination Switching of Antiferromagnetic Proximity Effect in Topological Insulator

August 12, 2020
Author(s)
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

Magnetic Phase Transitions and Spin Density Distribution in the Molecular Multiferroic System GaV 4 S 8

July 7, 2020
Author(s)
Rebecca L Dally, William D. Ratcliff, Lunyong Zhang, Heung-Sik Kim, Markus NMN Bleuel, J. W. Kim, Kristjan Haule, David Vanderbilt, Sang-Wook Cheong, Jeffrey W. Lynn
We have carried out neutron diffraction and small angle neutron scattering measurements on a high quality single crystal of the cubic lacunar spinel multiferroic, GaV 4S 8, as a function of magnetic field and temperature to determine the magnetic form

Electronic and Magnetic Properties of Stoichiometric CeAuBi 2

June 18, 2020
Author(s)
M. M. Piva, R. Tartaglia, G. S. Freitas, J. C. Souza, D. S. Christovam, S. M. Thomas, Juscelino Leao, William D. Ratcliff, Jeffrey W. Lynn, C. Lane, J.-X Zhu, J. D. Thompson, P. F. S. Rosa, C. Adriano, E. Granado, P. G. Pagliuso
We report the electronic and magnetic properties of stoichiometric CeAuBi 2 single crystals. At ambient pressure, CeAuBi 2 orders antiferromagnetically below a Neel temperature (T N ) of 19 K. Neutron diffraction experiments revealed an antiferromagnetic

Ferromagnetism in van der Waals Compound MnSb 1.8 Bi 0.2 Te 4

June 11, 2020
Author(s)
Yangyang Chen, Ya-Wen Chuang, Seng Huat Lee, Yanglin Zhu, Kevin Honz, Yingdong Guan, Yu Wang, Ke Wang, Zhiqiang Mao, Jun Zhu, Colin A. Heikes, Patrick Quarterman, P. Zajdel, Julie Borchers, William D. Ratcliff
The intersection of topology and magnetism represent a new playground to discover novel quantum phenomena and new device concepts. In this work, we show that a van der Waals compound MnSb 1.8 Bi 0.2Te 4 exhibits a ferromagnetic ground state with a Curie

Spin Rotation Induced by Applied Pressure in Cd-Doped Ce 2 RhIn 8 Intermetallic Compound

October 21, 2019
Author(s)
D. S. Christovam, C. Giles, L. Mendonca-Ferreira, Juscelino Leao, William D. Ratcliff, Jeffrey W. Lynn, S. Ramos, E. N. Hering, H. Hidaka, E. Baggio-Saitovich, Z. Fisk, P. G. Pagliuso, C. Adriano
The pressure evolution of the magnetic properties of the Ce 2RhIn 7.79Cd 0.21 heavy fermion compound was investigated by single crystal neutron magnetic diffraction and electrical resistivity experiments under applied pressure. From the neutron magnetic

Anharmonic Acoustic Phonons and A-site Critical Fluctuations in the Lead Halide Perovskite CsPbBr 3

September 17, 2019
Author(s)
M. Songvilay, Nathan Giles-Donovan, M. Bari, Z.-G. Ye, J. L. Minns, M. A. Green, Guangyong Xu, Peter M. Gehring, K. Schmalzl, William D. Ratcliff, Craig Brown, D. Chernyshov, W. van Beek, Sandy Cochran, Christopher Stock
We apply neutron spectroscopy to investigate the transverse acoustic phonons in the lead halide CsPbBr 3 near the three zone boundaries of the cubic Pm3m Brillouin zone at QX = (2,1/2,0), Q M = (3/2,1/2,0), and Q R = (1/2,1/2,3/2). CsPbB r3 undergoes two

Spin Scattering and Noncollinear Spin Structure-Induced Intrinsic Anomalous Hall Effect in Antiferromagnetic Topological Insulator MnBi 2 Te 4

August 19, 2019
Author(s)
Seng Huat Lee, Yanglin Zhu, Yu Wang, Leixin Miao, Timothy Pillsbury, Hemian Yi, Susan Kempinger, Jin Hu, Colin A. Heikes, Patrick Quarterman, William D. Ratcliff, Julie Borchers, Heda Zhang, Xianglin Ke, David Graf, Nasim Alem, Cui-Zu Chang, Nitin Samarth, Zhiqiang Mao
MnBi 2Te 4 has recently been established as an intrinsic antiferromagnetic (AFM) topological insulator - an ideal platform to create quantum anomalous Hall (QAH) insulator and axion insulator states. We performed comprehensive studies on the structure

Modification of Spin-Ice Physics in Ho 2 Ti 2 O 7 Thin Films

August 16, 2019
Author(s)
Kevin Barry, Biwen Zhang, Naween Anand, Yan Xin, Arturas Vailionis, Jennifer Neu, Colin A. Heikes, Charis Cochran, Haidong Zhou, Yiming Qiu, William D. Ratcliff, Theo Siegrist, Christianne Beekman
We report on a study of the structural and magnetic properties of strained Ho 2Ti 2O 7 thin films. Structural characterization via synchrotron x-ray diffraction confirms good crystallinity of our films and shows a critical thickness slightly below 50 nm