μ+e-Hyperfine Interactions in Quartz Crystals

1980 ◽  
Vol 3 ◽  
Author(s):  
J.H. Brewer ◽  
D.G. Fleming ◽  
D.P. Spencer
Keyword(s):  
Magnetic Field ◽  
Room Temperature ◽  
Hyperfine Interactions ◽  
Single Frequency ◽  
Zero Magnetic Field ◽  
Hydrogen Atoms ◽  
Frequency Oscillation ◽  
Quartz Crystals ◽  
Muonium Spin ◽  
Motional Narrowing

ABSTRACTLongitudinal muonium spin relaxation/modulation in zero magnetic field (zf-MSR) has been used to study muonium (μ+e-) atoms in single-crystal α-quartz between 5 K and room temperature. At 6 K, three frequencies are observed, corresponding to a triaxial hyperfine matrix whose principal values are close to those observed for hydrogen atoms frozen into known sites. For intermediate temperatures the Mu atoms “hop” between sites, causing a relaxation whose rate first increases with the hop rate and then decreases due to motional narrowing. Finally, at room temperature, a single-frequency oscillation is observed, corresponding to a uniaxial motionally-averaged hyperfine interaction.

Enhancement of the CMR Effect Near Room Temperature by Defects and Structural Transitions in La1−x−yCaxSryMnO3

1999 ◽  
Vol 602 ◽  
Author(s):  
S. Kolesnik ◽  
B. Dabrowski ◽  
Z. Bukowski ◽  
J. Mais
Keyword(s):  
Magnetic Field ◽  
Room Temperature ◽  
Structural Phase ◽  
Zero Magnetic Field ◽  
Ferromagnetic Transition ◽  
Spin Lattice ◽  
Preparation Conditions ◽  
Close Proximity ◽  
Selection Of ◽  
Structural Phase Transformations

AbstractWe have studied magnetoresistance of a series of La1−xSrxMnO3 and La1−x−yCaxSryMnO3 samples, for which structural and ferromagnetic transformation temperatures are in close proximity. On cooling in zero magnetic field, we observe a rapid increase of resistivity just above TC for La1−xSrxMnO3 samples with x < 0.1425 and x ≤ 0.1725 due to the O*-O' and R-O* - structural phase transformations, respectively. This increase is followed by a rapid decrease due to the ferromagnetic transition. The applied magnetic field significantly shifts the ferromagnetic transition to higher temperatures and suppresses the structure-related resistivity increase. We show that a combination of structural and ferromagnetic transitions gives rise to an enhancement of the negative magnetoresistance due to strong spin-lattice coupling. By choosing a proper composition, the enhancement can be optimized to appear in relatively low magnetic fields. A proper selection of Sr and Ca contents in La1−x−yCaxSryMnO3 and preparation conditions leads to an enhancement of the magnetoresistance effect at room temperature.

scholarly journals Skyrmion formation in a bulk chiral magnet at zero magnetic field and above room temperature

2017 ◽  
Vol 1 (7) ◽  
Author(s):  
K. Karube ◽  
J. S. White ◽  
D. Morikawa ◽  
M. Bartkowiak ◽  
A. Kikkawa ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Room Temperature ◽  
Zero Magnetic Field

Paramagnetic resonance and electron nuclear double resonance of substitutional hydrogen atoms in CaF 2

1967 ◽  
Vol 297 (1450) ◽  
pp. 376-396 ◽  
Keyword(s):  
Room Temperature ◽  
Endor Spectrum ◽  
Hyperfine Interactions ◽  
Double Resonance ◽  
Hydrogen Atoms ◽  
Electron Nuclear Double Resonance ◽  
Paramagnetic Resonance ◽  
Infrared Measurements ◽  
X Irradiation ◽  
Induced Defects

Recent infrared measurements have shown that hydrogen dissolves in CaF 2 as H - ions in fluorine sites (Elliott, Hayes, Jones, MacDonald & Sennett 1965). X-irradiation of CaF 2 : H crystals at room temperature produces paramagnetic hydrogen atoms in interstitial sites (Hall & Schumacher 1962). The present work shows that X-irradiation of CaF 2 : H crystals at 77°K produces hydrogen atoms in fluorine sites. These substitutional hydrogen atoms move into interstitial sites at 135°K giving rise to the e. p. r. spectrum observed by Hall & Schumacher in room temperature irradiated crystals. The present paper contains a detailed description of the e. p. r. and endor spectrum of the substitutional atoms in CaF 2 . It is found that the hyperfine interactions with second shell fluorines are smaller than with third and fourth shell fluorines and an explanation is suggested for this effect. Endor measurements of first shell fluorines show a resolved structure due to indirect fluorine-fluorine interactions. The endor measurements are of interest in connexion with the production and annealing mechanisms of the irradiation-induced defects.

MÖSSBAUER EFFECT STUDIES ON LITHIUM FERRITE SUBSTITUTED WITH CHROMIUM AND ANTIMONY

2003 ◽  
Vol 17 (02) ◽  
pp. 67-73 ◽  
Author(s):  
RADHAPIYARI LAISHRAM ◽  
CHANDRA PRAKASH ◽  
SUMITRA PHANJOUBAM ◽  
H. N. K. SARMA
Keyword(s):  
Magnetic Field ◽  
Quadrupole Splitting ◽  
Cation Distribution ◽  
Room Temperature ◽  
Hyperfine Interactions ◽  
Lithium Ferrite ◽  
Mossbauer Effect ◽  
Chromium Level ◽  
Ferrite System ◽  
Nuclear Magnetic

The effect of Cr 3+ concentration on the various hyperfine interactions for the ferrite system Li 0.5+t Cr x Sb t Fe 2.5-2t-x O 4, 0.0 ≤ x ≤ 1.0, x in steps of 0.2 and t = 0.1, have been studied at room temperature using Mössbauer spectroscopy. The isomershift and the quadrupole splitting are almost negligibly influenced by the change in chromium level. The internal nuclear magnetic field, as determined from the Mössbauer spectra and the linewidth are also studied with the variation of composition. The results have been explained on the basis of various models and a cation distribution has been worked out.

Cerium Doped Bismuth Antimony

2012 ◽  
Vol 1456 ◽  
Author(s):  
Kevin C. Lukas ◽  
Huaizhou Zhao ◽  
Ryan L. Stillwell ◽  
Zhifeng Ren ◽  
Cyril P. Opeil
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Single Crystals ◽  
Room Temperature ◽  
Zero Magnetic Field ◽  
Bismuth Antimony ◽  
Impurity Doping ◽  
Antimony Alloys

ABSTRACTBismuth-Antimony alloys have been shown to have high ZT values below room temperature, especially for single crystals. For polycrystalline samples, impurity doping and magnetic field have proven to be powerful tools in the search for understanding and improving thermoelectric performance. Nanopolycrystalline Bi0.88Sb0.12 doped with 0.05, 0.5 and 3 % Ce were prepared by ball milling and dc hot pressing techniques. Electrical resistivity, Seebeck coefficient, thermal conductivity, carrier concentration, mobility, and magnetization are measured in a temperature range of 5-350 K and in magnetic fields up to 9 Tesla. The effects of Ce doping on the thermoelectric properties of Bi0.88Sb0.12 in zero magnetic field are discussed.

scholarly journals Observation of magnetic skyrmions in unpatterned symmetric multilayers at room temperature and zero magnetic field

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
J. Brandão ◽  
D. A. Dugato ◽  
R. L. Seeger ◽  
J. C. Denardin ◽  
T. J. A. Mori ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Room Temperature ◽  
Zero Magnetic Field ◽  
Magnetic Skyrmions

Temperature Dependent Line-Shape of the Silicon Dangling Bond EPR-Resonance in Polycrystalline Silicon

1996 ◽  
Vol 452 ◽  
Author(s):  
N. H. Nickel ◽  
E. A. Schiff
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Polycrystalline Silicon ◽  
Room Temperature ◽  
Dangling Bond ◽  
Temperature Dependent ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Motional Narrowing ◽  
G Value ◽  
Electron Paramagnetic

AbstractThe temperature dependence of the silicon dangling-bond resonance in polycrystalline (poly-Si) and amorphous silicon (a-Si:H) was measured. At room temperature, electron paramagnetic resonance (EPR) measurements reveal an isotropie g-value of 2.0055 and a line width of 6.5 and 6.1 G for Si dangling-bonds in a-Si:H and poly-Si, respectively. In both materials spin density and g-value are independent of temperature. While in a-Si:H the width of the resonance did not change with temperature, poly-Si exhibits a remarkable T dependence of ΔHpp. In unpassivated poly-Si a pronounced decrease of ΔHpp is observed for temperatures above 300 K. At 384 K ΔHpp reaches a minimum of 5.1 G, then increases to 6.1 G at 460 K, and eventually decreases to 4.6 G at 530 K. In hydrogenated poly-Si ΔHpp decreases monotonically above 425 K. The decrease of ΔHpp is attributed to electron hopping causing motional narrowing. An average hopping distance of 15 and 17.5 Å was estimated for unhydrogenated and H passivated poly-Si, respectively.

scholarly journals All organic multiferroic magnetoelectric complexes with strong interfacial spin-dipole interaction

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Yuying Yang ◽  
Zhiyan Chen ◽  
Xiangqian Lu ◽  
Xiaotao Hao ◽  
Wei Qin
Keyword(s):  
Magnetic Field ◽  
Light Intensity ◽  
Room Temperature ◽  
Incident Light ◽  
Dipole Interaction ◽  
Interfacial Interaction ◽  
Magnetoelectric Coupling ◽  
Incident Light Intensity ◽  
Organic Ferromagnets ◽  
Magnetoelectric Coefficient

AbstractThe organic magnetoelectric complexes are beneficial for the development on flexible magnetoelectric devices in the future. In this work, we fabricated all organic multiferroic ferromagnetic/ferroelectric complexes to study magnetoelectric coupling at room temperature. Under the stimulus of external magnetic field, the localization of charge inside organic ferromagnets will be enhanced to affect spin–dipole interaction at organic multiferroic interfaces, where overall ferroelectric polarization is tuned to present an organic magnetoelectric coupling. Moreover, the magnetoelectric coupling of the organic ferromagnetic/ferroelectric complex is tightly dependent on incident light intensity. Decreasing light intensity, the dominated interfacial interaction will switch from spin–dipole to dipole–dipole interaction, which leads to the magnetoelectric coefficient changing from positive to negative in organic multiferroic magnetoelectric complexes.

Sign in / Sign up

Export Citation Format

Share Document