scholarly journals Dipolar field-induced asymmetric magnetization hysteresis of immobile superparamagnetic nanoclusters

2019 ◽  
Vol 480 ◽  
pp. 132-137 ◽  
Author(s):  
Suko Bagus Trisnanto ◽  
Yasushi Takemura
Keyword(s):  
Dipolar Field ◽  
Magnetization Hysteresis

scholarly journals Opacities in Strong Magnetic Helds

1995 ◽  
Vol 10 ◽  
pp. 588-590
Author(s):  
Dayal T. Wickramasinghe
Keyword(s):  
Entire Range ◽  
White Dwarfs ◽  
Specific Problem ◽  
Transition Probabilities ◽  
Strong Field ◽  
Energy Levels ◽  
Dipolar Field ◽  
Origin And Evolution ◽  
End Products ◽  
Hydrogen Lines

White dwarfs are one of the most readily studied end products of stellarevolution. Their observed properties have provided and continue to provide important constraints for the theory of stellar evolution. Likewise, a study of magnetism in white dwarfs provides unique insights into the origin and evolution of magnetic fields in stars.Spectacular progress has been made on the specific problem of the structure of the hydrogen atom in strong fields. Energy levels and transition probabilities are now known for all low lying states of hydrogen for the entire range of field strengths appropriate to white dwarfs and neutron stars (104-1013G) (Rosner et al 1984, Forster et al 1984 and Henry and O’Connell 1984). These calculations resulted in the identification of spectral features in the magnetic white dwarf Grw+70°8247 which had remained unidentified for over 50 years (Minkowski 1938), with Zeeman shifted hydrogen lines in a magnetic field of 100 -320 MG ((eg Wickamasinghe and Ferrano 1989). Several other strong field magnetic white dwarfs have since been discovered through hydrogen Zeeman spectroscopy. The data presently at hand show that most hydrogen rich magnetic white dwarfs have complex non-dipolar field structures with strong evidence for higher order multipole components.

Size Effects in Dynamics of Dipolar Planar Nanosystems

2004 ◽  
Vol 99-100 ◽  
pp. 223-226
Author(s):  
H. Puszkarski ◽  
J.-C.S. Lévy ◽  
M. Krawczyk
Keyword(s):  
Size Effects ◽  
Equations Of Motion ◽  
Sample Surface ◽  
Dipolar Field ◽  
Dipolar Interactions ◽  
Planar System ◽  
Frequency Spectra ◽  
Magnetostatic Waves ◽  
Dynamic Components ◽  
Field Static

The equations of motion are derived for a magnetic planar system with dipolar interactions taken into account. Magnetostatic waves propagating perpendicularly to the sample surface and dipolar field static and dynamic components are calculated for the case when saturating field is applied perpendicularly to the sample surface. The corresponding frequency spectra and mode profiles are computed numerically with emphasis laid on size effects. It is established that two lowest-frequency modes are surface-localized modes. These modes preserve their surface-localized character with growing sample dimensions.

Corrugated SNOM probe with enhanced energy throughput

2008 ◽  
Vol 16 (4) ◽  
Author(s):  
T. Antosiewicz ◽  
T. Szoplik
Keyword(s):  
Near Field ◽  
Three Dimensional ◽  
Energy Output ◽  
Dipolar Field ◽  
Two Dimensional ◽  
The Core ◽  
Dimensional Approximation ◽  
New Type ◽  
Difference Time ◽  
Main Factor

AbstractIn a previous paper we proposed a modification of metal-coated tapered-fibre aperture probes for scanning near-field optical microscopes (SNOMs). The modification consists in radial corrugations of the metal-dielectric interface oriented inward the core. Their purpose is to facilitate the excitation of surface plasmons, which increase the transport of energy beyond the cut-off diameter and radiate a quasi-dipolar field from the probe output rim. An increase in energy output allows for reduction of the apex diameter, which is the main factor determining the resolution of the microscope. In two-dimensional finite-difference time-domain (FDTD) simulations we analyse the performance of the new type of SNOM probe. We admit, however, that the two-dimensional approximation gives better results than expected from exact three-dimensional ones. Nevertheless, optimisation of enhanced energy throughput in corrugated probes should lead to at least twice better resolution with the same sensitivity of detectors available nowadays.

Electron spin resonance of paramagnetic impurities in antiferromagnetic compounds

1991 ◽  
Vol 433 (1888) ◽  
pp. 461-468 ◽  
Keyword(s):  
Internal Field ◽  
Host Lattice ◽  
Nuclear Resonance ◽  
Dipolar Field ◽  
Exchange Field ◽  
Paramagnetic Impurities ◽  
Resonance Frequencies ◽  
Spin Resonance ◽  
Impurity Ions ◽  
Impurity Ion

The possibility of magnetic resonance measurements on an impurity in an antiferromagnetic host lattice is discussed. The ion is subject to an internal field B int ; consisting of B dip , the dipolar field generated by the antiferromagnetic moments of the host ions, that can be calculated, and an exchange field B E . For a simple two sublattice antiferromagnet, two resonance frequencies should be observed; equations for their angular dependence are given, including the effect of hyperfine interaction. Impurity ions with Kramers doublets are discussed, together with ions with singlet ground states, for which enhanced nuclear resonance should be possible. A number of simple antiferromagnetic compounds of lanthanide (4f) ions that order at liquid helium temperatures are mentioned briefly, but for simplicity, the discussion is concentrated on GdVO 4 as the host lattice. A formula, based on the known exchange field in the host lattice, is deduced for its effect on the impurity ion.

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