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Full-Text Articles in Physics
Electrostatic Potential And Valence Modulation In La0.7sr0.3mno3 Thin Films, Robbyn Trappen, A. C. Garcia- Castro, Vu Thanh Tra, Chih-Yeh Huang, Wilfredo Ibarra-Hernandez, James Fitch, Sobhit Singh, Jingling Zhou, Guerau Cabrera, Ying-Hao Chu, James M. Lebeau, Aldo H. Romero, Mikel B. Holcomb
Electrostatic Potential And Valence Modulation In La0.7sr0.3mno3 Thin Films, Robbyn Trappen, A. C. Garcia- Castro, Vu Thanh Tra, Chih-Yeh Huang, Wilfredo Ibarra-Hernandez, James Fitch, Sobhit Singh, Jingling Zhou, Guerau Cabrera, Ying-Hao Chu, James M. Lebeau, Aldo H. Romero, Mikel B. Holcomb
Faculty & Staff Scholarship
The Mn valence in thin film La0.7Sr0.3MnO3 was studied as a function of film thickness in the range of 1–16 unit cells with a combination of non-destructive bulk and surface sensitive X-ray absorption spectroscopy techniques. Using a layer-by-layer valence model, it was found that while the bulk averaged valence hovers around its expected value of 3.3, a significant deviation occurs within several unit cells of the surface and interface. These results were supported by first principles calculations. The surface valence increases to up to Mn3.7+, whereas the interface valence reduces down to Mn2.5+. The change in valence from the expected …
Cavitons And Spontaneous Hot Flow Anomalies In A Hybrid-Vlasov Global Magnetospheric Simulation, Xochitl Blanco-Cano, Markus Battarbee, Lucile Turc, Andrew P. Dimmock, Emilia K.J. Kilpua, Sanni Hoilijoki, Urs Ganse, David G. Sibeck, Paul A. Cassak, Robert C. Fear, Riku Jarvinen, Liisa Juusola, Yann Pfau-Kempf, Rami Vainio, Minna Palmroth
Cavitons And Spontaneous Hot Flow Anomalies In A Hybrid-Vlasov Global Magnetospheric Simulation, Xochitl Blanco-Cano, Markus Battarbee, Lucile Turc, Andrew P. Dimmock, Emilia K.J. Kilpua, Sanni Hoilijoki, Urs Ganse, David G. Sibeck, Paul A. Cassak, Robert C. Fear, Riku Jarvinen, Liisa Juusola, Yann Pfau-Kempf, Rami Vainio, Minna Palmroth
Faculty & Staff Scholarship
Abstract. In this paper we present the first identification of foreshock cavitons and the formation of spontaneous hot flow anomalies (SHFAs) with the Vlasiator global magne- tospheric hybrid-Vlasov simulation code. In agreement with previous studies we show that cavitons evolve into SHFAs. In the presented run, this occurs very near the bow shock. We report on SHFAs surviving the shock crossing into the down- stream region and show that the interaction of SHFAs with the bow shock can lead to the formation of a magnetosheath cavity, previously identified in observations and simulations. We report on the first identification of long-term …
Robust Topological Phase In Proximitized Core–Shell Nanowires Coupled To Multiple Superconductors, Tudor D. Stanescu, Anna Stitek, Andrei Manolescu
Robust Topological Phase In Proximitized Core–Shell Nanowires Coupled To Multiple Superconductors, Tudor D. Stanescu, Anna Stitek, Andrei Manolescu
Faculty & Staff Scholarship
We consider core–shell nanowires with prismatic geometry contacted with two or more superconductors in the presence of a mag- netic field applied parallel to the wire. In this geometry, the lowest energy states are localized on the outer edges of the shell, which strongly inhibits the orbital effects of the longitudinal magnetic field that are detrimental to Majorana physics. Using a tight-binding model of coupled parallel chains, we calculate the topological phase diagram of the hybrid system in the presence of non-vanishing transverse potentials and finite relative phases between the parent superconductors. We show that having finite relative phases strongly …
Learning Local, Quenched Disorder In Plasticity And Other Crackling Noise Phenomena, Stefanos Papanikolaou
Learning Local, Quenched Disorder In Plasticity And Other Crackling Noise Phenomena, Stefanos Papanikolaou
Faculty & Staff Scholarship
When far from equilibrium, many-body systems display behavior that strongly depends on the initial conditions. A characteristic such example is the phenomenon of plasticity of crystalline and amorphous materials that strongly depends on the material history. In plasticity modeling, the history is captured by a quenched, local and disordered flow stress distribution. While it is this disorder that causes avalanches that are commonly observed during nanoscale plastic deformation, the functional form and scaling properties have remained elusive. In this paper, a generic formalism is developed for deriving local disorder distributions from field- response (e.g., stress/strain) timeseries in models of crackling …
Insights Into The Magnetic Dead Layer In La0.7sr0.3mno3 Thin Films From Temperature, Magnetic Field And Thickness Dependence Of Their Magnetization, N. Mottaghi, M.S. Seehra, R. Trappen, S. Kumari, Chih-Yeh Huang, S. Yousefi, G.B. Cabrera, A.H. Romero, M.B. Holcomb
Insights Into The Magnetic Dead Layer In La0.7sr0.3mno3 Thin Films From Temperature, Magnetic Field And Thickness Dependence Of Their Magnetization, N. Mottaghi, M.S. Seehra, R. Trappen, S. Kumari, Chih-Yeh Huang, S. Yousefi, G.B. Cabrera, A.H. Romero, M.B. Holcomb
Faculty & Staff Scholarship
Experimental investigations of the magnetic dead layer in 7.6 nm thick film of La0.7Sr0.3MnO3 (LSMO) are reported. The dc magnetization (M) measurements for a sample cooled to T = 5 K in applied field H = 0 reveal the presence of negative remanent magnetization (NRM) in the M vs. H (magnetic field) measurements as well as in the M vs. T measurements in H = 50 Oe and 100 Oe. The M vs. T data in ZFC (zero-field-cooled) and FC (field-cooled) protocols are used to determine the blocking temperature TB in different H. Isothermal hysteresis loops at differ- ent T …
Graphene Nanoplatelets-Sericin Surface-Modified Gum Alloy For Improved Biological Response, Valentina Mitran, Valentina Dinca, Raluca Ion, Vasile D. Cojocaru, Patricia Neacsu, Cerasela Zoica Dinu, Laurentiu Rusen, Simona Brajnicov, Anca Bonciu, Maria Dinescu, Doina Raducanu, Ioan Dan
Graphene Nanoplatelets-Sericin Surface-Modified Gum Alloy For Improved Biological Response, Valentina Mitran, Valentina Dinca, Raluca Ion, Vasile D. Cojocaru, Patricia Neacsu, Cerasela Zoica Dinu, Laurentiu Rusen, Simona Brajnicov, Anca Bonciu, Maria Dinescu, Doina Raducanu, Ioan Dan
Faculty & Staff Scholarship
In this study a “Gum Metal” titanium-based alloy, Ti-31.7Nb-6.21Zr-1.4Fe-0.16O, was synthesized by melting and characterized in order to evaluate its potential for biomedical applications. The results showed that the newly developed alloy presents a very high strength, high plasticity and a low Young's modulus relative to titanium alloys currently used in medicine. For further bone implant applications, the newly synthesized alloy was surface modified with graphene nanoplatelets (GNP), sericin (SS) and graphene nanoplatelets/sericine (GNP–SS) composite films via Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. The characterization of each specimen was monitored by scanning electron microscopy (SEM), atomic force microscopy (AFM), …
Single-Site Catalyst Promoters Accelerate Metal- Catalyzed Nitroarene Hydrogenation, Liang Wang, Erjia Guan, Jian Zhang, Junhao Yang, Yihan Zhu, Yu Han, Ming Yang, Cheng Cen, Gang Fu, Bruce C. Gates, Feng-Shou Xiao
Single-Site Catalyst Promoters Accelerate Metal- Catalyzed Nitroarene Hydrogenation, Liang Wang, Erjia Guan, Jian Zhang, Junhao Yang, Yihan Zhu, Yu Han, Ming Yang, Cheng Cen, Gang Fu, Bruce C. Gates, Feng-Shou Xiao
Faculty & Staff Scholarship
Atomically dispersed supported metal catalysts are drawing wide attention because of the opportunities they offer for new catalytic properties combined with efficient use of the metals. We extend this class of materials to catalysts that incorporate atomically dispersed metal atoms as promoters. The catalysts are used for the challenging nitroarene hydro- genation and found to have both high activity and selectivity. The promoters are single-site Sn on TiO2 supports that incorporate metal nanoparticle catalysts. Represented as M/Sn- TiO2 (M = Au, Ru, Pt, Ni), these catalysts decidedly outperform the unpromoted supported metals, even for hydrogenation of nitroarenes substituted with various …
Induced Ferromagnetism In Multilayered Graphene In Proximity With Cofe2o4, Himanshu Verma, Dereje Seifu, Shashi P. Karna, Haiping Hong, Mohindar S. Seehra
Induced Ferromagnetism In Multilayered Graphene In Proximity With Cofe2o4, Himanshu Verma, Dereje Seifu, Shashi P. Karna, Haiping Hong, Mohindar S. Seehra
Faculty & Staff Scholarship
Composites of anisotropic diamagnetic multilayer Graphene (MLG) and ferrimagnetic CoFe2O4 (CFO) nanoparticles (NPs) were synthesized through a one-step sonication process in the presence of a surfactant. The samples were characterized at ambi- ent using x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy, magnetic force microscopy (MFM) and magnetometry (vibrating sample magnetometer). An induced ferromagnetism was observed in MLG with saturation magnetization MS = 18 emu/g(MLG). This induced ferromagnetism is attributed to ferrimagnetic CFO uniformly distributed on the surface of diamagnetic MLG. SEM images confirm uniform dense distribu- tion of CFO nanoparticles on MLG. MFM images …