ESR STUDIES OF GMR RELATED MATERIALS I: ESR of Mn IN LaMnO3 AND La0.99Ca0.01MnO3

2000 ◽  
Vol 14 (25n26) ◽  
pp. 883-897 ◽  
Author(s):  
N. ARAI ◽  
K. SUGAWARA
Keyword(s):  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Spin System ◽  
High Field ◽  
Energy Gap ◽  
Low Field ◽  
High Field Esr ◽  
Clear Signal ◽  
Spin Clusters ◽  
G Value

ESR measurements are carried out for La 1-x Ca x MnO 3 (x=0, 0.01) from 760 K down to 4 K. A clear signal was observed above 260 K, presumably arising from Mn 3+ and Mn 4+, but two kinds of signals, the low-field and high-field ESR with g≃2, were observed below it. The high- and low-field signals are tentatively assumed to originate from Mn 4+ and Mn 3+, respectively. The g-value, linewidth, and intensity of the high-field signal nearly follow ∝1/(T-106). The temperature dependence of g-shift of the low-field signal is similar to that of magnetic susceptibility of LaMnO 3. The ESR intensity anomalously increases at temperatures between about 150 K and 250 K, which is tentatively ascribed to the occurrence of "spin-clusters". Above ≃300 K, the ESR intensity nearly follows Curie's law, and the linewidth is proportional to exp (-500/T), an indication of some kind of energy-gap existence in the Mn spin system.

High-field ESR measurements of quantum spin system under high pressure

2003 ◽  
Vol 329-333 ◽  
pp. 963-964 ◽  
Author(s):  
M SARUHASHI
Keyword(s):  
High Pressure ◽  
Spin System ◽  
High Field ◽  
Quantum Spin ◽  
Quantum Spin System ◽  
High Field Esr

Determination of Density of Localized States in Amorphous Silicon Alloys From the Low Field Conductance of Thin N-I-N Diodes

1985 ◽  
Vol 49 ◽  
Author(s):  
Michael Shur ◽  
Michael Hack
Keyword(s):  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Bulk Density ◽  
Density Of States ◽  
Energy Gap ◽  
Localized States ◽  
New Technique ◽  
Silicon Alloys ◽  
Low Field ◽  
Density Of Localized States

AbstractWe describe a new technique to determine the bulk density of localized states in the energy gap of amorphous silicon alloys from the temperature dependence of the low field conductance of n-i-n diodes. This new technique allows us to determine the bulk density of states in the centre of a device, and is very straightforward, involving fewer assumptions than other established techniques. Varying the intrinsic layer thickness allows us to measure the,density of states within approximately 400 meV of midgap.We measured the temperature dependence of the low field conductance of an amorphous silicon alloy n-i-n diode with an intrinsic layer thjckness of 0.45 microns and deduced the density of localised states to be 3xlO16cm−3 eV−1 at approximately 0.5 eV below the bottom of the conduction band. We have also considered the high bias region (the space charge limited current regime) and proposed an interpolation formula which describes the current-voltage characteristics of these structures at all biases and agrees well with our computer simulation based on the solution of the complete system of transport equations.

Observation of direct transition in quantum spin system Cu2(C5N12N2)2Cl4 by high-field ESR

2001 ◽  
Vol 226-230 ◽  
pp. 439-440 ◽  
Author(s):  
H Ohta ◽  
Y Oshima ◽  
T Sakurai ◽  
S Okubo ◽  
T Tanaka ◽  
...  
Keyword(s):  
Spin System ◽  
High Field ◽  
Quantum Spin ◽  
Quantum Spin System ◽  
Direct Transition ◽  
High Field Esr

scholarly journals Thermomagnetic properties of vivianite nodules, Lake El'gygytgyn, Northeast Russia

2012 ◽  
Vol 8 (5) ◽  
pp. 4989-5027 ◽  
Author(s):  
P. S. Minyuk ◽  
T. V. Subbotnikova ◽  
L. L. Brown ◽  
K. J. Murdock
Keyword(s):  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Magnetic Measurements ◽  
Iron Phosphate ◽  
Northeastern Russia ◽  
Northeast Russia ◽  
Low Field ◽  
Lake El’Gygytgyn ◽  
Monoclinic Pyrrhotite ◽  
Thermomagnetic Properties

Abstract. Vivianite, a hydrated iron phosphate, is abundant in sediments of El'gygytgyn Lake, located in the Anadyr Mountains of Central Chukotka, Northeastern Russia (67° 30' N; 172° 05' E). Magnetic measurements, including weight low-field AC magnetic susceptibility, field dependent magnetic susceptibility, hysteresis parameters, temperature dependence of the saturation magnetization, as well as susceptibility in different heating media provide ample information on vivianite. Electron-microprobe analyses, electron microscopy and energy dispersive spectroscopy were used to identify diagnostic minerals. Vivianite nodules are abundant in both sediments of cold (anoxic) and warm (oxic) stages. Magnetic susceptibility of the nodules varies from 0.78 × 10−6 m3 kg−1 to 1.72 × 10−6 m3 kg−1 (average = 1.05 × 10−6 m3 kg−1) and is higher than the susceptibility of sediments from the cold intervals. Magnetic properties of vivianite are due to product of oxidation as well as sediment and mineral inclusions. Three types of curves of high temperature dependence susceptibility of vivianite indicate different degree of oxidation and inclusions in the nodules. Vivianite acts as a reductant and reduces hematite to magnetite and suppresses the goethite-hematite transition during heating. Heating vivianite and sulfur mixture stimulate the formation of monoclinic pyrrhotite. An additive of arsenic inhibits the formation of magnetite prior to its Curie temperature. Heating selective vivianite and pyrite mixtures produces formation of several different minerals – magnetite, monoclinic pyrrhotite, and hexagonal pyrrhotite, and make it difficult to interpret the thermomagnetic curves.

scholarly journals High field ESR measurements on the chiral spin system CuB2O4

2006 ◽  
Vol 51 ◽  
pp. 111-114 ◽  
Author(s):  
T Fujita ◽  
Y Fujimoto ◽  
S Mitsudo ◽  
T Idehara ◽  
K Inoue ◽  
...  
Keyword(s):  
Spin System ◽  
High Field ◽  
High Field Esr

High-field ESR in a two-dimensional S=1 spin system Ni5(TeO3)4Br2

2007 ◽  
Vol 316 (2) ◽  
pp. e349-e351 ◽  
Author(s):  
Denis Arčon ◽  
Andrej Zorko ◽  
Matej Pregelj ◽  
Janez Dolinšek ◽  
Helmuth Berger ◽  
...  
Keyword(s):  
Spin System ◽  
High Field ◽  
Two Dimensional ◽  
High Field Esr

Temperature dependence of the magnetic properties of reservoir rocks and minerals and implications for in situ borehole predictions of petrophysical parameters

Geophysics ◽  
2012 ◽  
Vol 77 (3) ◽  
pp. WA211-WA221 ◽  
Author(s):  
Arfan Ali ◽  
David K. Potter
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
High Field ◽  
Magnetic Measurements ◽  
Clay Content ◽  
Petrophysical Parameters ◽  
Reservoir Rocks ◽  
Fluid Permeability

Recent work has shown strong correlations between magnetic susceptibility and key petrophysical parameters such as clay content and fluid permeability. The magnetic measurements in previous work were mainly undertaken at ambient (room temperature) conditions on core samples. The present study involved theoretical modeling and experimentation on the temperature dependence of the magnetic properties (mass magnetization and magnetic susceptibility) of reservoir rocks and minerals over a range of low and high applied fields. It paves the way for correctly interpreting borehole magnetic susceptibility measurements, and accurately predicting petrophysical properties in situ, from a potentially new suite of low and high field borehole magnetic tools. The temperature dependent magnetic susceptibility measurements provide an improved means of quantifying the diamagnetic versus paramagnetic mineral content in reservoir rocks compared to a single ambient measurement. Paramagnetic clays, such as illite, are important in controlling the fluid permeability in many of these samples, and we again saw correlations between the magnetic measurements, paramagnetic clay content, and permeability. We also show how to derive ferrimagnetic mineral hysteresis curves by subtracting the high field magnetic data from the total signal. The resulting magnetic hysteresis curves give important information concerning the content (often only a few ppm, which X-ray diffraction cannot detect), mineralogy, and domain state of the ferrimagnetic particles.

The temperature dependence of the low field magnetoresistance in electron-doped manganites: La1 xTexMnO3(x= 0.04,0.1)

2004 ◽  
Vol 16 (8) ◽  
pp. 1447-1453 ◽  
Author(s):  
Guotai Tan ◽  
Ping Duan ◽  
Guang Yang ◽  
Shouyu Dai ◽  
Bolin Cheng ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Low Field ◽  
Doped Manganites

Sequential assignment of NMR spectra of peptides at natural isotopic abundance with Zero and Ultra-Low Field-TOCSY

2021 ◽  
Author(s):  
Alexey S. Kiryutin ◽  
Ivan V. Zhukov ◽  
Fabien Ferrage ◽  
G Bodenhausen ◽  
Alexandra V. Yurkovskaya ◽  
...  
Keyword(s):  
High Field ◽  
Nmr Spectra ◽  
Correlation Spectroscopy ◽  
Sequential Assignment ◽  
Isotopic Abundance ◽  
Natural Isotopic Abundance ◽  
Low Field ◽  
Total Correlation ◽  
High Resolution Nmr ◽  
Novel Method

A novel method dubbed ZULF-TOCSY results from the combination of Zero and Ultra-Low Field (ZULF) with high-field, high-resolution NMR, leading to a generalization of the concept of total correlation spectroscopy...

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