Magnetic anisotropies and relative aromaticities of pyrrole, pyrazole, imidazole and their N-methyl derivatives

1981 ◽  
Vol 34 (9) ◽  
pp. 1835 ◽  
Author(s):  
KE Calder ◽  
RL Calvert ◽  
PB Lukins ◽  
GLD Ritchie
Keyword(s):  
Magnetic Anisotropy ◽  
Dipole Moments ◽  
Effective Polarizability ◽  
Plane Component ◽  
Out Of Plane ◽  
Local Contribution ◽  
Non Local ◽  
Methyl Derivatives ◽  
Methyl Imidazole ◽  
Kerr Constants

Experimental dipole moments, molar Kerr constants and molar Cotton-Mouton constants at 298 K and 633 nm are reported for pyrrole, pyrazole, imidazole and their N-methyl derivatives as solutes in dioxan. Analysis of the Kerr-effect data yields the effective polarizability anisotropies which are used to evaluate the molecular magnetic anisotropies from the Cotton-Mouton constants. The magnetic criterion of aromaticity is applied by estimating for each molecule the non-local contribution to the out-of-plane component of the magnetizability and the magnetic anisotropy. Electron delocalization in these molecules is significantly less than that exhibited by benzene: pyrrole and N-methylpyrrole, c. 70%; pyrazole and N-methylpyrazole, c. 65%; imidazole and N-methyl-imidazole, c. 60%. Approximately one-third of the observed magnetic anisotropy arises from localized contributions.

Molar Kerr constants and solute polarizability anisotropies of ammonia, trimethylamine, trimethylamine oxide and 1,4-Diazabicyclo[2,2,2]octane

1977 ◽  
Vol 30 (7) ◽  
pp. 1411 ◽  
Author(s):  
RS Armstrong ◽  
MJ Aroney ◽  
KE Calderbank ◽  
RK Pierens
Keyword(s):  
Dipole Moment ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Polar Solvents ◽  
Effective Polarizability ◽  
Electric Dipole Moments ◽  
Trimethylamine Oxide ◽  
Solute Interactions ◽  
Kerr Constants

Electric dipole moments and molar Kerr constants are reported for ammonia, trimethylamine, trimethylamine oxide, 1,4- diazabicyclo[2,2,2]octane and its monohydrate in non-polar solvents. The dipole moment now found for 1,4-diazabicyclo[2,2,2]octane differs substantially from previously recorded values. Effective polarizability anisotropies are derived for each of the anhydrous molecules and for the N-H and N-C bonds. The effect of solute interactions with benzene is explored.

Conformation of ring A in 3-oxotriterpenoids. Dipole moments and CD spectra

1986 ◽  
Vol 51 (3) ◽  
pp. 611-620 ◽  
Author(s):  
Jiří Klinot ◽  
Václav Všetečka ◽  
Eva Klinotová ◽  
Alois Vystrčil
Keyword(s):  
Dipole Moments ◽  
Cd Spectra ◽  
Boat Form ◽  
Methyl Derivatives

The A ring of 3-oxotriterpenoids allobetulone (I) and 3-xo-lupane-28-nitrile (IV) exists by about 40% in the boat form as derived from comparison of their dipole moments with those of 2α-methyl derivatives II, V (chair models) and 2β-methyl compounds III, VI (boat models). The same result was obtained from the CD spectra of 3-oxotriterpenoids I-VIII and from isomerization of the 2α- and 2β-substituted ketones XI and XII, respectively.

Realizing large out-of-plane magnetic anisotropy in L10-FeNi films grown by nitrogen-surfactant epitaxy on Cu(001)

2020 ◽  
Vol 4 (5) ◽  
Author(s):  
Kaishu Kawaguchi ◽  
Toshio Miyamachi ◽  
Takushi Iimori ◽  
Yuki Takahashi ◽  
Takuma Hattori ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Out Of Plane

Magnetic out-of-plane component in MnAs/GaAs(001)

2003 ◽  
Vol 83 (14) ◽  
pp. 2850-2852 ◽  
Author(s):  
A. Ney ◽  
T. Hesjedal ◽  
C. Pampuch ◽  
J. Mohanty ◽  
A. K. Das ◽  
...  
Keyword(s):  
Plane Component ◽  
Out Of Plane

scholarly journals Route towards efficient magnetization reversal driven by voltage control of magnetic anisotropy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Roxana-Alina One ◽  
Hélène Béa ◽  
Sever Mican ◽  
Marius Joldos ◽  
Pedro Brandão Veiga ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Random Access ◽  
Low Power Consumption ◽  
Surface Anisotropy ◽  
Magnetization Dynamics ◽  
Storage Density ◽  
Switching Regime ◽  
Major Interest ◽  
Out Of Plane

AbstractThe voltage controlled magnetic anisotropy (VCMA) becomes a subject of major interest for spintronics due to its promising potential outcome: fast magnetization manipulation in magnetoresistive random access memories with enhanced storage density and very low power consumption. Using a macrospin approach, we carried out a thorough analysis of the role of the VCMA on the magnetization dynamics of nanostructures with out-of-plane magnetic anisotropy. Diagrams of the magnetization switching have been computed depending on the material and experiment parameters (surface anisotropy, Gilbert damping, duration/amplitude of electric and magnetic field pulses) thus allowing predictive sets of parameters for optimum switching experiments. Two characteristic times of the trajectory of the magnetization were analyzed analytically and numerically setting a lower limit for the duration of the pulses. An interesting switching regime has been identified where the precessional reversal of magnetization does not depend on the voltage pulse duration. This represents a promising path for the magnetization control by VCMA with enhanced versatility.

scholarly journals Non-monotonic magnetic anisotropy behavior as a function of adsorbate coverage in Fe ultrathin films near the spin reorientation transition

2021 ◽  
Author(s):  
A. Quesada ◽  
G. Chen ◽  
A. T. N'Diaye ◽  
P. Wang ◽  
Y. Z. Wu ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Magnetic Anisotropy ◽  
Ultrathin Films ◽  
Co Adsorption ◽  
Spin Reorientation ◽  
Spin Reorientation Transition ◽  
Out Of Plane

Carbon monoxide (CO) adsorption on ultrathin fcc Fe films is known to result in the rotation of magnetization from out-of-plane to in-plane.

Effect of substrates on the out-of-plane magnetic anisotropy in Au/Co/Au sandwiches

1996 ◽  
Vol 154 (2) ◽  
pp. 160-164 ◽  
Author(s):  
P. Beauvillain ◽  
C. Chappert ◽  
K. Le Dang ◽  
R. Mégy ◽  
S. Ould Mahfoud ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Out Of Plane
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