scholarly journals Manganese doping for enhanced magnetic brightening and circular polarization control of dark excitons in paramagnetic layered hybrid metal-halide perovskites

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Timo Neumann ◽  
Sascha Feldmann ◽  
Philipp Moser ◽  
Alex Delhomme ◽  
Jonathan Zerhoch ◽  
...  
Keyword(s):  
Circular Polarization ◽  
Quantum Interference ◽  
Magnetic Moments ◽  
Manganese Doping ◽  
Polarization Control ◽  
Saturation Polarization ◽  
Powerful Approach ◽  
State Mixing ◽  
Excitonic States ◽  
Dark Exciton

AbstractMaterials combining semiconductor functionalities with spin control are desired for the advancement of quantum technologies. Here, we study the magneto-optical properties of novel paramagnetic Ruddlesden-Popper hybrid perovskites Mn:(PEA)2PbI4 (PEA = phenethylammonium) and report magnetically brightened excitonic luminescence with strong circular polarization from the interaction with isolated Mn2+ ions. Using a combination of superconducting quantum interference device (SQUID) magnetometry, magneto-absorption and transient optical spectroscopy, we find that a dark exciton population is brightened by state mixing with the bright excitons in the presence of a magnetic field. Unexpectedly, the circular polarization of the dark exciton luminescence follows the Brillouin-shaped magnetization with a saturation polarization of 13% at 4 K and 6 T. From high-field transient magneto-luminescence we attribute our observations to spin-dependent exciton dynamics at early times after excitation, with first indications for a Mn-mediated spin-flip process. Our findings demonstrate manganese doping as a powerful approach to control excitonic spin physics in Ruddlesden-Popper perovskites, which will stimulate research on this highly tuneable material platform with promise for tailored interactions between magnetic moments and excitonic states.

Circular Polarization Control in Silicon-Based All-Optical Switch

2005 ◽  
Vol 44 (7A) ◽  
pp. 4749-4751 ◽  
Author(s):  
Naokatsu Yamamoto ◽  
Toshiaki Matsuno ◽  
Hiroshi Takai ◽  
Naoki Ohtani
Keyword(s):  
Circular Polarization ◽  
Optical Switch ◽  
Polarization Control ◽  
All Optical ◽  
All Optical Switch ◽  
Silicon Based

Frequency Tunable Circular Polarization Control of Terahertz Radiation

2005 ◽  
Vol 44 (No. 21) ◽  
pp. L676-L678 ◽  
Author(s):  
Ryo Shimano ◽  
Hisaaki Nishimura ◽  
Tomohiro Sato
Keyword(s):  
Circular Polarization ◽  
Terahertz Radiation ◽  
Polarization Control ◽  
Frequency Tunable

scholarly journals Dressed excitonic states and quantum interference in a three-level quantum dot ladder system

2009 ◽  
Vol 11 (1) ◽  
pp. 013028 ◽  
Author(s):  
B D Gerardot ◽  
D Brunner ◽  
P A Dalgarno ◽  
K Karrai ◽  
A Badolato ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Quantum Interference ◽  
Ladder System ◽  
Excitonic States

Nickel Nanocomposite Thin Films

2001 ◽  
Vol 703 ◽  
Author(s):  
Honghui Zhou ◽  
A. Kvit ◽  
D. Kumar ◽  
J. Narayan
Keyword(s):  
Quantum Interference ◽  
Magnetic Measurements ◽  
Magnetic Moments ◽  
Deposition Process ◽  
Blocking Temperature ◽  
Ni Nanoparticles ◽  
Epitaxial Relationship ◽  
Transmission Electron ◽  
Nanocomposite Thin Films ◽  
Matrix Layer

ABSTRACTNickel was deposited on epitaxial TiN matrix layer grown on Si (100) substrate by pulsed laser deposition process (PLD). Transmission electron microscopy (TEM) study shows that nanoparticles formed are single crystals with two kinds of epitaxial relationship with respect to matrix TiN. One is cube on cube, where (200) Ni // (200) TiN // (200) Si and (022) Ni // (022) TiN // (022) Si. The particles grown in this orientation have a trapezoidal morphology in [011] projection. The other involves a 90 ° rotation with respect to [011] direction of TiN matrix (zone axis), where (022) Ni // (200) TiN // (200) Si and (200) Ni // (022) TiN // (022) Si. The particles grown in this rotated orientation have a triangular morphology in [011] projection and a smaller lattice constant compared with that of pure nickel. The possible mechanism of forming these two epitaxial orientations is discussed. Superconducting quantum interference device (SQUID) magnetometer was used for magnetic measurements. In order to investigate the effect of texturing on magnetic properties of nanoparticles, results were compared with those obtained from Ni nanoparticles grown on amorphous Al2O3 matrix layer in previous research. It was found that both blocking temperature and coercivity of Ni nanoparticles grown on epitaxial TiN matrix are significantly higher than that of Ni grown on amorphous Al2O3. The higher value of coercivity is possibly associated with the stronger tendency of crystallographically oriented particles to retain their magnetic moments in the presence of reversing magnetic field.

Microscopic description of ground state magnetic moment and low-lying magnetic dipole excitations in heavy odd-mass 181Ta nucleus

2016 ◽  
Vol 25 (08) ◽  
pp. 1650053 ◽  
Author(s):  
Emre Tabar ◽  
Hakan Yakut ◽  
Ali Akbar Kuliev
Keyword(s):  
Excited States ◽  
Magnetic Dipole ◽  
Ground State ◽  
Magnetic Moments ◽  
Nuclear Model ◽  
Spurious State ◽  
Restoration Method ◽  
State Mixing ◽  
Self Consistency

The ground state magnetic moments and the low-lying magnetic dipole (Ml) transitions from the ground to excited states in heavy deformed odd-mass [Formula: see text]Ta have been microscopically investigated on the basis of the quasiparticle-phonon nuclear model (QPNM). The problem of the spurious state mixing in M1 excitations is overcome by a restoration method allowing a self-consistent determination of the separable effective restoration forces. Due to the self-consistency of the method, these effective forces contain no arbitrary parameters. The results of calculations are compared with the available experimental data, the agreement being reasonably satisfactory.

scholarly journals ELECTROMAGNETIC PROCESSES IN χEFT

2009 ◽  
Vol 24 (11n13) ◽  
pp. 931-936 ◽  
Author(s):  
S. PASTORE ◽  
R. SCHIAVILLA ◽  
J. L. GOITY
Keyword(s):  
Field Theory ◽  
Circular Polarization ◽  
Cross Section ◽  
Effective Field Theory ◽  
Magnetic Moments ◽  
Effective Field ◽  
Polarization Parameter ◽  
Chiral Effective Field Theory ◽  
Electromagnetic Processes ◽  
Theory Framework

Nuclear electromagnetic currents derived in a chiral-effective-field-theory framework including explicit nucleons, Δ isobars, and pions up to N2LO, i.e. ignoring loop corrections, are used in a study of neutron radiative captures on protons and deuterons at thermal energies, and of A=2 and 3 nuclei magnetic moments. With the strengths of the Δ-excitation currents determined to reproduce the n-p cross section and isovector combination of the trinucleon magnetic moments, we find that the cross section and photon circular polarization parameter, measured respectively in n-d and [Formula: see text] processes, are significantly underpredicted by theory.

scholarly journals Electric-field control of magnetic moment in Pd

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Aya Obinata ◽  
Yuki Hibino ◽  
Daichi Hayakawa ◽  
Tomohiro Koyama ◽  
Kazumoto Miwa ◽  
...  
Keyword(s):  
Electric Field ◽  
Magnetic Moment ◽  
Proximity Effect ◽  
Quantum Interference ◽  
Magnetic Moments ◽  
Magnetic Phase Transitions ◽  
Magnetic Element ◽  
Fundamental Parameters ◽  
Magnetic Elements ◽  
Clear Change

Abstract Several magnetic properties have recently become tunable with an applied electric field. Particularly, electrically controlled magnetic phase transitions and/or magnetic moments have attracted attention because they are the most fundamental parameters in ferromagnetic materials. In this study, we showed that an electric field can be used to control the magnetic moment in films made of Pd, usually a non-magnetic element. Pd ultra-thin films were deposited on ferromagnetic Pt/Co layers. In the Pd layer, a ferromagnetically ordered magnetic moment was induced by the ferromagnetic proximity effect. By applying an electric field to the ferromagnetic surface of this Pd layer, a clear change was observed in the magnetic moment, which was measured directly using a superconducting quantum interference device magnetometer. The results indicate that magnetic moments extrinsically induced in non-magnetic elements by the proximity effect, as well as an intrinsically induced magnetic moments in ferromagnetic elements, as reported previously, are electrically tunable. The results of this study suggest a new avenue for answering the fundamental question of “can an electric field make naturally non-magnetic materials ferromagnetic?”

Polarization control of an X-ray free-electron laser with a diamond phase retarder

2014 ◽  
Vol 21 (3) ◽  
pp. 466-472 ◽  
Author(s):  
Motohiro Suzuki ◽  
Yuichi Inubushi ◽  
Makina Yabashi ◽  
Tetsuya Ishikawa
Keyword(s):  
Circular Polarization ◽  
Free Electron ◽  
Free Electron Laser ◽  
X Rays ◽  
Horizontal Polarization ◽  
X Ray ◽  
Polarization Control ◽  
Diamond Phase ◽  
Thick Crystal ◽  
High Degree

A diamond phase retarder was applied to control the polarization states of a hard X-ray free-electron laser (XFEL) in the photon energy range 5–20 keV. The horizontal polarization of the XFEL beam generated from the planar undulators of the SPring-8 Angstrom Compact Free-Electron Laser (SACLA) was converted into vertical or circular polarization of either helicity by adjusting the angular offset of the diamond crystal from the exact Bragg condition. Using a 1.5 mm-thick crystal, a high degree of circular polarization, 97%, was obtained for 11.56 keV monochromatic X-rays, whereas the degree of vertical polarization was 67%, both of which agreed with the estimations including the energy bandwidth of the Si 111 beamline monochromator.

Effect of Distribution of Functionalized Magnetic Nanoparticles on Ferrogel Actuation

2010 ◽  
Author(s):  
Kamlesh J. Suthar ◽  
Muralidhar K. Ghantasala ◽  
Derrick C. Mancini ◽  
Joseph E. Mowat ◽  
Jan Ilavsky
Keyword(s):  
Magnetic Field ◽  
Quantum Interference ◽  
Particle Distribution ◽  
Magnetic Moments ◽  
Crosslinking Density ◽  
Magnetic Characteristics ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Functionalized Magnetic Nanoparticles ◽  
Set Up

The ferrogels elongate, contract, and deflect in response to an applied magnetic field. In order to study its response to magnetic fields, ferrogels were prepared using meghamite (Fe304) nanoparticles (size ∼ 10–25 nm) using the hydrogel based on N-isopropylacrylamide (NIPAm). The particle distribution is determined for different cross-linking density of the gel in the range of 2% to 8%. The ferrogels were analyzed using ultra small angle x-ray scattering (USAXS) and the particle distribution were compared with direct imaging of the samples using transmission electron microscopy. The uniformity of the distribution of the particles for different samples prepared was determined using USAXS. Magnetic characteristics of the ferrogel were determined using a direct current superconducting quantum interference device (DC-Squid). The magnetic moments of the polyvinylpyrrolidone (PVP) coated Fe3O4 nanoparticles based ferrogel are reduced from 2.5 – 0.4 emu/g, as the particle concentration is decreased from 8.75 to 1.25%. Subsequently, the deflection and strain also reduced under static magnetic field. These studies showed that a maximum deflection of 20% and strain of 10% to its original value could be achieved by varying the particle size and/or distribution. The crosslinking ratio of the polymer was varied from 1.2 – 8%. The deflection and elongation characteristics were studied using a custom-built electromagnetic set-up with a pole gap of 10 mm with magnetic field strength up to 2500 Gauss. However, the maximum strain reduces as the crosslinking density increases. This study clearly shows the dependence of the deflection and strain on the functionalization material coated on the particle. Details of the results of our experiments are presented in this paper.

Enhanced Room-Temperature Ferromagnetism in Superconducting Pr2-xCexCuO4 Nanoparticles

2019 ◽  
Vol 966 ◽  
pp. 263-268
Author(s):  
Malik Anjelh Baqiya ◽  
Putu Eka Dharma Putra ◽  
Resky Irfanita ◽  
Suasmoro ◽  
Darminto ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Quantum Interference ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Magnetic Moments ◽  
Weak Ferromagnetism ◽  
Superconducting Transition ◽  
Superconducting Quantum Interference Device ◽  
To Come

Recently, the so-called room-temperature ferromagnetism in any nanoparticles has been studied intensively. It is well known that the properties of ferromagnetism and superconductivity are contradictory in a superconducting high-Tc cuprate. The existence of ferromagnetism in the nanoparticles has been suggested to occur on the surface. This magnetism has been expected to come from defects inducing magnetic moments on oxygen vacancies at the surface of the nanoparticles. This work is to observe magnetism in nanosized superconducting Pr2-xCexCuO4 (PCCO) with x = 0.15 by means of a superconducting quantum interference device (SQUID). The magnetization curves of the reduced PCCO nanoparticles with the superconducting transition temperature, Tc, of ~25 K have revealed that there is weak ferromagnetism observed at room temperature. The magnitude of magnetization could be enhanced by oxygen reduction annealing in vacuum with increasing annealing temperature. A non-linear magnetization occurring in the reduced PCCO nanoparticles through the vacuum annealing process is probably due to a strong oxygen reduction producing more oxygen vacancies in the T'-structure.

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