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Articles 1 - 8 of 8
Full-Text Articles in Physics
Understanding The Spin-Glass State Through The Magnetic Properties Of Mn-Doped Znte, A. Alcantara, S. Barrett, D. Matev, I. Miotkowski, A. K. Ramdas, T. Pekarek, J. T. Haraldsen
Understanding The Spin-Glass State Through The Magnetic Properties Of Mn-Doped Znte, A. Alcantara, S. Barrett, D. Matev, I. Miotkowski, A. K. Ramdas, T. Pekarek, J. T. Haraldsen
Showcase of Osprey Advancements in Research and Scholarship (SOARS)
Magnetic measurements on the spin-glass behavior in the bulk II-VI diluted magnetic semiconductor (DMS) ZnMnTe were made on two crystals of concentrations x = 0.43 and 0.55 taken from the same boule. Magnetization and density functional theory studies have shown paramagnetic behavior in both samples between 30 and 400 K. Below 30 K, there is a prominent peak at Tc = 15 and 23.6 K for concentrations x = 0.43 and 0.55, respectively. The splitting of the field cooled (FC) and zero field cooled (ZFC) data below this peak is indicative of a transition to a spin-glass state at low …
Investigation Of The Obscure Spin State Of Ti-Doped Cdse, J. Dimuna, T. Boyett, I. Miotkowski, A. K. Ramdas, T. Pekarek, J. T. Haraldsen
Investigation Of The Obscure Spin State Of Ti-Doped Cdse, J. Dimuna, T. Boyett, I. Miotkowski, A. K. Ramdas, T. Pekarek, J. T. Haraldsen
Showcase of Osprey Advancements in Research and Scholarship (SOARS)
Using computational and experimental techniques, we examine the nature of the 2+ oxidation of Ti-doped CdSe. Through stoichiometry and confirmed through magnetization measurements, the weakly-doped material of Cd1-xTixSe (x = 0.0043) shows the presence of a robust spin-1 magnetic state of Ti, which is indicative of a 2+ oxidation state. Given the obscure nature of the Ti2+ state, we investigate the electronic and magnetic states using density functional theory. Using a generalized gradient approximation with an onsite potential, we determine the electronic structure, magnetic moment density, and optical properties for a supercell of CdSe with an ultra-low concentration of Ti. …
Electronic And Magnetic Order As A Function Of Doping In Mixed-Valent La1-Xsrxmn03 Thin Films, James Payne, Dakota Brown, Calleigh Brannan, Tom Pekarek, Maitri Warusawithana
Electronic And Magnetic Order As A Function Of Doping In Mixed-Valent La1-Xsrxmn03 Thin Films, James Payne, Dakota Brown, Calleigh Brannan, Tom Pekarek, Maitri Warusawithana
Showcase of Osprey Advancements in Research and Scholarship (SOARS)
The rich phase diagram in mixed-valent manganites has been intensely studied in bulk crystals as a function of chemical doping. Here we study the effect of doping in La1-xSrxMnO3 thin films by varying the Sr/La ratio between samples. These thin films are grown using ozone assisted molecular beam epitaxy with carefully controlled stoichiometry for a range of doping from x = 0.0 to x = 0.5. Our electronic measurements reveal a crossover from a Mott insulator to a metallic ground state as x is increased. In the metallic ground state we observe a metal-to-insulator transition coincident with a ferromagnetic-to-paramagnetic ordering …
Improving Photon Number Resolution In Superconducting Nanowire Single-Photon Detectors With Integrated Impedance Tapers, Bladimiro E. Valbuena, Daniel F. Santavicca
Improving Photon Number Resolution In Superconducting Nanowire Single-Photon Detectors With Integrated Impedance Tapers, Bladimiro E. Valbuena, Daniel F. Santavicca
Showcase of Osprey Advancements in Research and Scholarship (SOARS)
Simulations are run to optimize the ability to resolve the number of photons detected from the pulse height by a Superconducting Nanowire Single-Photon Detector (SNSPD). This is set up in a manner that features an impedance-matching transmission line taper that provides a characteristic impedance which transitions from kΩ to 50 Ω, with the taper providing an effective load impedance that outputs pulses with not only larger amplitudes but also showed a distinct separation for multi-photon events. The first part of this project tries to computationally match the experimental results obtained by our collaborators at MIT. Once these results are achieved, …
Understanding The Magnetic Interactions Of The Zig-Zag Honeycomb Lattice: Application To Rucl3, Evan Wilson, Jason T. Haraldsen
Understanding The Magnetic Interactions Of The Zig-Zag Honeycomb Lattice: Application To Rucl3, Evan Wilson, Jason T. Haraldsen
Showcase of Osprey Advancements in Research and Scholarship (SOARS)
The new field of Dirac quantum matter has produced a lot of interesting theories and materials, especially in the dynamics of magnetic materials. One such material is RuCl3, which is a S = 1/2 zigzag honeycomb lattice. Through inelastic neutron scattering, this material has demonstrated spin waves with an energy scale of 1.5-8.0 meV. According to literature, RuCl3 may be the realization of a new theoretical phase of matter called a spin liquid. This materials seems to fit the profile and has been investigated using a Kitaev model. In this study, we re-examine the data for RuCl3 using a standard …
Magnetic Properties Of Mbe Grown La1/3y1/3sr1/3mno3 Thin Films And Superlattices, W. A. Ruiz, C. Kengle, J. Payne, D. Brown, W. P. Warusawithana, T. M. Pekarek
Magnetic Properties Of Mbe Grown La1/3y1/3sr1/3mno3 Thin Films And Superlattices, W. A. Ruiz, C. Kengle, J. Payne, D. Brown, W. P. Warusawithana, T. M. Pekarek
Showcase of Osprey Advancements in Research and Scholarship (SOARS)
We have investigated the magnetic properties of thin films related to the standard CMR system La2/3Sr1/3MnO3 where Y substituted for 50% of the La atoms. These La1/3Y1/3Sr1/3MnO3 films were grown as a random alloy where La, Y, and Sr atoms randomly occupied the A-site or as a superlattice where each unit-cell-thick layer stacked along the crystallographic (001) direction contained only one of the atoms La, Y, and Sr occupying the A-site. One of the key magnetic features of La2/3Sr1/3MnO3 is a prominent ferromagnetic transition near 350 K. We find the substitution of La with Y suppresses this ferromagnetic transition in …
Spin-Glass Ordering In The Diluted Magnetic Semiconductor Zn1-Xmnxte, S. Barrett, T. M. Pekarek
Spin-Glass Ordering In The Diluted Magnetic Semiconductor Zn1-Xmnxte, S. Barrett, T. M. Pekarek
Showcase of Osprey Advancements in Research and Scholarship (SOARS)
Magnetic measurements on the spin-glass behavior in the bulk II-VI diluted magnetic semiconductor (DMS) ZnMnTe were made on two crystals of concentrations x = 0.43 and 0.55 taken from the same boule. Magnetization and density functional theory studies have shown paramagnetic behavior in both samples between 30 and 400 K. Below 30 K, there is a prominent peak at Tc = 15 and 23.6 K for concentrations x = 0.43 and 0.55, respectively. The splitting of the field cooled (FC) and zero field cooled (ZFC) data below this peak is indicative of a transition to a spin-glass state at low …
Reduced Dimensionality Effects In Ferromagnetic Behavior In La1-Xsrxmno3, C. A. Brennan, M. P. Warusawithana, J. Payne, D. Brown, T. M. Pekarek
Reduced Dimensionality Effects In Ferromagnetic Behavior In La1-Xsrxmno3, C. A. Brennan, M. P. Warusawithana, J. Payne, D. Brown, T. M. Pekarek
Showcase of Osprey Advancements in Research and Scholarship (SOARS)
We study the magnetic properties of La1-xSrxMnO3 samples for concentrations x, 0 ≤ x ≤ 0.5. An analysis is done to accurately determine the transition temperature or critical temperature. Magnetic phase diagrams showing the various concentrations at different temperatures will be determined for our thin films. Using the phase diagrams for both bulk and thin film materials can show how reducing the dimensionality from the third dimension to approaching the second-dimension affects the phase diagram.