scholarly journals Der Antiferromagnetismus des Ferritins bei Messungen der magnetischen Suszeptibilität im Temperaturbereich von 4,2 bis 300°K

1965 ◽  
Vol 20 (2) ◽  
pp. 167-172 ◽  
Author(s):  
Georg Schoffa
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Structure ◽  
Magnetic Moment ◽  
Exchange Constant ◽  
Antiferromagnetic Exchange ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Temperature Range ◽  
Experimental Values ◽  
Oxygen Atoms

Measurements of magnetic susceptibility in the temperature range 4.2-300°K show that ferritin is antiferromagnetic with a Néel temperature of 20° ± 3°K. The theory of J. S. SMART for antiferromagnetic exchange between iron atoms clustered in groups of two (“isolated clusters”) gives the best agreement between theoretical and experimental values. The antiferromagnetic exchange constant is J/k=- 4.8 (°K). Reduced magnetic moment for µeff =3.85 μB is due to the transfer of two electrons from oxygen atoms to ferric atoms caused on the cation-anion-cation superexchange. Some models of superexchange are discussed. Antiferromagnetism and superexchange are possibly caused on the cubic magnetic structure of iron-oxygen micelles in ferritin.

scholarly journals Magnetic and Electrical Transport Properties of Vanadium Telluride

1980 ◽  
Vol 35 (7) ◽  
pp. 701-703 ◽  
Author(s):  
C. Prasad ◽  
R. A. Singh
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Magnetic Susceptibility ◽  
Electrical Transport ◽  
Powdered Sample ◽  
Neel Temperature ◽  
Electrical Transport Properties ◽  
Néel Temperature ◽  
Paramagnetic Curie Temperature ◽  
Temperature Range

Measurements of the magnetic susceptibility of a powdered sample of VTe in the temperature range 90 - 700 K, and of the a.c. electrical conductivity (σ), thermoelectric power (θ) and dielectric constant (ε′) of pressed pellets of the compound in the temperature range 300 -1100 K are reported. The compound is found to be antiferromagnetic with Neel temperature 420 ± 5 K. The effective paramagnetic moment and paramagnetic Curie temperature are found to be 1.6 μB and - 250 K, respectively. The dependence of σ, θ and ε′ on temperature shows no anomaly at the Neel temperature and is indicative of the metallic nature of the compound.

ANTIFERROMAGNETIC ORDERING IN Y-BA-CU-PT-O

1987 ◽  
Vol 01 (02) ◽  
pp. 479-484 ◽  
Author(s):  
V.T. Kovachev ◽  
E.S. Vlakhov ◽  
K.A. Nenkov ◽  
V.A. Lovchinov ◽  
M.M. Gospodinov ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
High Temperature ◽  
Magnetic Moment ◽  
Neel Temperature ◽  
Néel Temperature ◽  
High Temperature Superconducting ◽  
Antiferromagnetic Ordering

A high temperature superconducting Y-Ba-Cu-Pt-O compound has been investigated. The results on magnetization and magnetic susceptibility of the compound are presented. A hysteresis of the magnetic moment at 4.2K is observed. This hysteresis occures, most probably, due to an antiferromagnetic ordering in the material. The Curie asymtotic temperature and Nèel temperature of the material are reported.

scholarly journals Characteristics of Coherent Optical Phonons in a Hexagonal YMnO3 Thin Film

2019 ◽  
Vol 9 (4) ◽  
pp. 704 ◽  
Author(s):  
Takayuki Hasegawa
Keyword(s):  
Thin Film ◽  
Optical Phonon ◽  
Laser Pulses ◽  
Generation Process ◽  
Neel Temperature ◽  
Optical Phonons ◽  
Néel Temperature ◽  
Temperature Range ◽  
Lower Temperature Range ◽  
Lower Temperature

This paper reviews our recent study on a coherent optical phonon in a hexagonal YMnO3 thin film together with related optical studies in hexagonal RMnO3 (R = Y, Lu, Ho) compounds. Coherent phonons have been observed in RMnO3 compounds by pump-probe spectroscopy with subpicosecond laser pulses, whereas the observation of coherent optical phonons was reported only in LuMnO3. Recently, we succeeded in the observation of the coherent optical phonon in a YMnO3 thin film. The generation process of the coherent optical phonon is assigned to a displacive mechanism, which is identical to that in LuMnO3. The coherent optical phonon is observed in the temperature range from 10 K to room temperature, while the oscillation intensity strongly decreases as the temperature increases to the Néel temperature of ~70 K from a lower temperature range. It is interesting that the temperature dependence is largely different from that in LuMnO3. We describe that the result can be qualitatively explained by the property of an isostructural transition around the Néel temperature in RMnO3 compounds. In addition, we briefly discuss ultrafast incoherent responses of excited electronic states from the viewpoint of the excitation photon energy of laser pulses.

AsPh4)2[Re2FN2Cl7], ein μ-Fluoro-Nitridokomplex des Rhenium(VI) / (AsPh4)2[Re2FN2Cl7],a μ-Fluoro Nitrido Complex of Rhenium(VI)

1980 ◽  
Vol 35 (3) ◽  
pp. 326-328 ◽  
Author(s):  
Werner Liese ◽  
Kurt Dehnicke ◽  
Jürgen Pebler
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Moment ◽  
Ir Spectrum ◽  
Effective Magnetic Moment ◽  
Complex Anion ◽  
Acetonitrile Solution ◽  
Temperature Range

(AsPh4)2[Re2FN2Cl7] is prepared by the reaction of ReNCL4 with AsPh4F in acetonitrile solution. The IR spectrum indicates a bridging Re-F-Re complex anion with terminal Re ≡ N ligands. The magnetic susceptibility was measured in the temperature range of 4.8-280 K. The effective magnetic moment is 1.66 B.M. per Re atom (θ = -0.5 K) and corresponds well with Re(VI). The magnetic moment of the well known PPh4[ReNCl4] has also been studied {μeff = 1.67 B.M.; θ = -1.2 K).

Crystal growth and physical properties of an antiferromagnetic molecule: trans-dibromidotetrakis(acetonitrile)chromium(III) tribromide, [CrBr2(NCCH3)4](Br3)

2021 ◽  
Vol 77 (4) ◽  
Author(s):  
Ranuri S. Dissanayaka Mudiyanselage ◽  
Tai Kong ◽  
Weiwei Xie
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Measurements ◽  
Interaction Analysis ◽  
Theoretical Calculations ◽  
Magnetic Feature ◽  
Maximum Temperature ◽  
Neel Temperature ◽  
X Ray Diffraction ◽  
Néel Temperature ◽  
X Ray

The synthesis, crystal structure determination, magnetic properties and bonding interaction analysis of a novel 3d transition-metal complex, [CrBr2(NCCH3)4](Br3), are reported. Single-crystal X-ray diffraction results show that [CrBr2(NCCH3)4](Br3) crystallizes in space group C2/m (No. 12) with a symmetric tribromide anion and the powder X-ray diffraction results show the high purity of the material specimen. X-ray photoelectron studies with a combination of magnetic measurements demonstrate that Cr adopts the 3+ oxidation state. Based on the Curie–Weiss analysis of magnetic susceptibility data, the Néel temperature is found to be around 2.2 K and the effective moment (μeff) of Cr3+ in [CrBr2(NCCH3)4](Br3) is ∼3.8 µB, which agrees with the theoretical value for Cr3+. The direct current magnetic susceptibility of the molecule shows a broad maximum at ∼2.3 K, which is consistent with the theoretical Néel temperature. The maximum temperature, however, shows no clear frequency dependence. Combined with the observed upturn in heat capacity below 2.3 K and the corresponding field dependence, it is speculated that the low-temperature magnetic feature of a broad transition in [CrBr2(NCCH3)4](Br3) could originate from a crossover from high spin to low spin for the split d orbital level low-lying states rather than a short-range ordering solely; this is also supported by the molecular orbital diagram obtained from theoretical calculations.

Phase Transition in Ultrathin Films

2014 ◽  
Vol 215 ◽  
pp. 227-232 ◽  
Author(s):  
Leonid L. Afremov ◽  
Aleksandr A. Petrov
Keyword(s):  
Phase Transition ◽  
Percolation Threshold ◽  
Ultrathin Films ◽  
Critical Concentration ◽  
Crystalline Lattice ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Average Spin ◽  
Experimental Values

Within the frame of average spin the dependence of Neel temperature of ultrathin antiferromagnetic film for FCC crystalline lattice on its thickness and the concentration of magnetic atoms has been defined. The λ values calculated by us are close to experimental values obtained for the films СoO/SiO2. The increasing of thickness leads to decreasing of the critical concentration down to the value equal to percolation threshold.

Peculiarities of Transport, Resonance and Optical Properties of the Anion-Substituted Manganese Chalcogenides

2015 ◽  
Vol 233-234 ◽  
pp. 447-450 ◽  
Author(s):  
O.B. Romanova ◽  
Sergei S. Aplesnin ◽  
A.M. Vorotynov ◽  
G.I. Makovetskii ◽  
O.F. Demidenko ◽  
...  
Keyword(s):  
Optical Properties ◽  
Magnetic Fields ◽  
Electron Structure ◽  
Optical Methods ◽  
Neel Temperature ◽  
Magnetoresistance Effect ◽  
Néel Temperature ◽  
Temperature Range ◽  
Maximum Value

The transport, resonance and optical properties of anion-substituted manganese chalcogenides MnSe1-xTex in the 77-300 K temperature range in magnetic fields up to 1T are studied. The magnetoresistance effect with the maximum value in the vicinity of the Neel temperature for the composition x = 0.1 is revealed. EPR data indirectly indicate the type of the current carriers – lattice polarons. The changes in electron structure occurring due to the anionic substitution are studied using the optical methods.

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