Determination of the mechanism of cation ordering in magnesioferrite (MgFe 2 O 4 ) from the time- and temperature-dependence of magnetic susceptibility

1999 ◽  
Vol 26 (4) ◽  
pp. 322-332 ◽  
Author(s):  
R. J. Harrison ◽  
A. Putnis
Keyword(s):  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Cation Ordering

Bestimmung elastischer Konstanten von MBBA und EBBA mit der elektrischen Leitfähigkeitsmethode / Determination of the Elastic Constants of MBBA and EBBA by Electric Conductivity Measurements

1975 ◽  
Vol 30 (4) ◽  
pp. 515-518 ◽  
Author(s):  
M. Greulich ◽  
G. Heppke ◽  
F. Schneider
Keyword(s):  
Magnetic Susceptibility ◽  
Liquid Crystals ◽  
Temperature Dependence ◽  
Electric Conductivity ◽  
Elastic Constants ◽  
Nematic Liquid Crystals ◽  
Elastic Behaviour ◽  
Conductivity Measurements

Abstract Several methods of studying the elastic behaviour of nematic liquid crystals by means of measuring the electric conductivity are discussed. The temperature dependence of the ratio of the splay and bend elastic constants to the anisotropy of the magnetic susceptibility is determined for N-(p-methoxybenzylidene) -p-n-butylaniline (MBBA), N-(p-ethoxybenzylidene) -p-n-butylaniline (EBBA) and mixtures of both.

Nuclear orientation of 54Mn in magnetically ordered MnCl2∙4H2O

1977 ◽  
Vol 55 (17) ◽  
pp. 1526-1540 ◽  
Author(s):  
R. L. A. Gorling ◽  
B. G. Turrell ◽  
P. W. Martin
Keyword(s):  
Magnetic Field ◽  
Field Theory ◽  
Heat Transfer ◽  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Nuclear Orientation ◽  
Antiferromagnetic Phase ◽  
Molecular Fields ◽  
Antiferromagnetic Spin

The antiferromagnetic, spin-flop, and paramagnetic phases of MnCl2∙4H2O have been investigated by observing the nuclear orientation of radioactive 54Mn in a single crystal of the salt. The directions of the sublattice magnetizations in the absence of an external magnetic field were determined. The field dependence of the sublattice magnetizations in the spin-flop state indicated that second order anisotropy is significant in this system. Furthermore, the measurements allowed the determination of the molecular fields in the molecular field theory. The spin-flop transition region was found to be described adequately by a domain structure in which regions of antiferromagnetic phase and spin-flop phase co-exist in the crystal. The temperature dependence of the spin-flop field was determined by magnetic susceptibility measurements. It was found that the spin-flop field decreases with decreasing temperature down to temperatures less than 0.1 K contrary to previous reports. The cooling of the specimen in contact with a copper heat sink was investigated and the temperature dependence of the heat transfer is discussed. An attempt to observe magnetic resonance of the oriented nuclei was unsuccessful.

Determination of Temperature Dependence of Kerr Constant for Nematic Liquid Crystal

2011 ◽  
Vol 544 (1) ◽  
pp. 227/[1215]-231/[1219] ◽  
Author(s):  
M. H. Majles Ara ◽  
S. H. Mousavi ◽  
M. Rafiee ◽  
M. S. Zakerhamidi
Keyword(s):  
Liquid Crystal ◽  
Temperature Dependence ◽  
Nematic Liquid Crystal ◽  
Kerr Constant

A neutron powder diffraction determination of the thermal expansion tensor of crocoite (PbCrO4) between 60 K and 290 K

1996 ◽  
Vol 60 (403) ◽  
pp. 963-972 ◽  
Author(s):  
Kevin S. Knight
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Powder Diffraction ◽  
Maximum Expansion ◽  
Lattice Constants ◽  
Thermal Expansion Tensor ◽  
Diffraction Determination ◽  
Line Passing ◽  
Neutron Time

AbstractThe thermal expansion tensor of crocoite has been determined from high-resolution neutron time-of-flight powder diffraction data. The temperature dependence of the lattice constants between 4.5 K and 290 K have been fitted to a quasi-harmonic Einstein model, and the temperature dependence of the thermal expansion tensor has been calculated for 60 K ≤ T ≤ 290 K. The magnitudes of the principal expansivities and their orientation exhibit saturation behaviour for temperatures above 300 K. The predicted saturated expansion coefficients are α11 = 33.1(1) × 10−6K−1, α22 = 15.72(3) × 10−6K−1, α33 = 3.36(1) × 10−6K−1, with α22 parallel to b and α11 lying at an angle of −37.86(5)° to c for the P21/n setting of the crystal structure. The direction of maximum expansion is approximately parallel to both and the least-squares line passing through the projection of the chromium atoms on (010). The direction of minimum expansion lies approximately parallel to [101]. No evidence was found for either a structural or magnetic phase transition between 4.5 K and 300 K.

The direct determination of the temperature dependence of the refractive index of liquids and solids

1976 ◽  
Vol 9 (14) ◽  
pp. 1945-1951 ◽  
Author(s):  
G Abbate ◽  
A Attanasio ◽  
U Bernini ◽  
E Ragozzino ◽  
F Somma
Keyword(s):  
Refractive Index ◽  
Temperature Dependence ◽  
Direct Determination
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