A New Magnetooptical Effect Discovered on Magnetic Multilayers: The Magnetorefractive Effect

1995 ◽  
Vol 384 ◽  
Author(s):  
J. C. Jacquet ◽  
T. Valet
Keyword(s):  
Magnetic Field ◽  
Optical Transmission ◽  
Theoretical Calculations ◽  
Wavelength Region ◽  
Magnetic Multilayers ◽  
Light Wavelength ◽  
Metallic Multilayers ◽  
Magnetooptical Effect ◽  
Transmission Measurements ◽  
Magnetorefractive Effect

ABSTRACTWe show theoretically that the change in the magnetization structure of magnetic metallic multilayers under the application of a magnetic field shall be generally associated with a significant change of the refractive index. This constitutes a new magnetooptical effect: the magnetorefractive effect.Optical transmission measurements under an applied magnetic field through [Ni80Fe20/Cu/Co/Cu] multilayers, in the light wavelength region between 2 μm and 20 μm, clearly demonstrate the existence of the predicted effect and are found in reasonnable agreement with the theoretical calculations.

Optical Transmission Measurements Through Samples Of Colloidal Graphite Under Magnetic Field

1977 ◽  
Vol 6 (1) ◽  
pp. 1-4 ◽  
Author(s):  
J. B. Bhagat ◽  
D. M. Bhagat ◽  
R. V. Mehta ◽  
H. S. Shah
Keyword(s):  
Magnetic Field ◽  
Optical Transmission ◽  
Colloidal Graphite ◽  
Transmission Measurements

Magnetooptical Properties of GaSe near the Band Gap

1973 ◽  
Vol 51 (5) ◽  
pp. 497-504 ◽  
Author(s):  
J. L. Brebner
Keyword(s):  
Magnetic Field ◽  
Band Gap ◽  
Field Data ◽  
Optical Transmission ◽  
Zero Field ◽  
High Quality ◽  
Effective Masses ◽  
Conduction Bands ◽  
Transmission Measurements ◽  
The Magnetic Field

Optical transmission measurements have been made on thin high quality crystals of GaSe in fields of up to 93.5 kG. The fields were aligned parallel and perpendicular to the ψ axis. The symmetries of the valence and conduction bands are discussed in the light of the zero field data, and subsequently the behavior of the excitons in the magnetic field is discussed. Values for the effective masses of holes and electrons normal to the ψ axis are determined to be 0.45m0 and 0.20m0 respectively. The values of the g factors parallel and perpendicular to the ψ axis are also deduced.

scholarly journals Terahertz characterization of two-dimensional low-conductive layers enabled by metal gratings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Prashanth Gopalan ◽  
Yunshan Wang ◽  
Berardi Sensale-Rodriguez
Keyword(s):  
Optical Transmission ◽  
Terahertz Spectroscopy ◽  
Design Guidelines ◽  
Two Dimensional ◽  
Highly Sensitive ◽  
Transmission Measurements ◽  
Metal Gratings ◽  
Low Sensitivity ◽  
Non Destructive

AbstractWhile terahertz spectroscopy can provide valuable information regarding the charge transport properties in semiconductors, its application for the characterization of low-conductive two-dimensional layers, i.e., σs <  < 1 mS, remains elusive. This is primarily due to the low sensitivity of direct transmission measurements to such small sheet conductivity levels. In this work, we discuss harnessing the extraordinary optical transmission through gratings consisting of metallic stripes to characterize such low-conductive two-dimensional layers. We analyze the geometric tradeoffs in these structures and provide physical insights, ultimately leading to general design guidelines for experiments enabling non-contact, non-destructive, highly sensitive characterization of such layers.

scholarly journals Colossal anomalous Nernst effect in a correlated noncentrosymmetric kagome ferromagnet

2021 ◽  
Vol 7 (13) ◽  
pp. eabf1467
Author(s):  
T. Asaba ◽  
V. Ivanov ◽  
S. M. Thomas ◽  
S. Y. Savrasov ◽  
J. D. Thompson ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electronic Structure ◽  
Theoretical Calculations ◽  
Zero Magnetic Field ◽  
Nernst Effect ◽  
Nodal Lines ◽  
Transverse Response ◽  
Narrow Bands ◽  
Strong Spin ◽  
Anomalous Nernst Effect

The transverse voltage generated by a temperature gradient in a perpendicularly applied magnetic field, termed the Nernst effect, has promise for thermoelectric applications and for probing electronic structure. In magnetic materials, an anomalous Nernst effect (ANE) is possible in a zero magnetic field. We report a colossal ANE in the ferromagnetic metal UCo0.8Ru0.2Al, reaching 23 microvolts per kelvin. Uranium’s 5f electrons provide strong electronic correlations that lead to narrow bands, a known route to producing a large thermoelectric response. In addition, uranium’s strong spin-orbit coupling produces an intrinsic transverse response in this material due to the Berry curvature associated with the relativistic electronic structure. Theoretical calculations show that in UCo0.8Ru0.2Al at least 148 Weyl nodes, and two nodal lines, exist within 60 millielectron volt of the Fermi level. This work demonstrates that magnetic actinide materials can host strong Nernst and Hall responses due to their combined correlated and topological nature.

Transition Metal-Doped ZnO: A Comparison of Optical, Magnetic, and Structural Behavior of Bulk and Thin Films

2006 ◽  
Vol 957 ◽  
Author(s):  
William E. Fenwick ◽  
Matthew H. Kane ◽  
Zaili Fang ◽  
Tahir Zaidi ◽  
Nola Li ◽  
...  
Keyword(s):  
Thin Films ◽  
Transition Metal ◽  
Optical Transmission ◽  
Magnetic Hysteresis ◽  
Structural Quality ◽  
Bulk Crystals ◽  
Transmission Measurements ◽  
Doped Zno ◽  
Metal Doped ◽  
Metal Incorporation

ABSTRACTTransition metal-doped ZnO bulk crystals and thin films have been investigated to determine the effects of transition metal incorporation on optical, magnetic, and structural properties of ZnO. A modified melt growth technique was used to grow bulk Zn1-xMnxO, Zn1-xCoxO, and Zn1-xFexO. Optical transmission measurements show an apparent shift in absorption edge with increasing transition metal incorporation. Raman spectroscopy also shows increasing lattice disorder with increasing transition metal concentration. ZnO thin films doped with Ni, Co, and Gd were grown by metalorganic chemical vapor deposition (MOCVD). While the Co-doped thin films showed antiferromagnetic behavior, magnetic hysteresis was observed in the Ni-doped and Gd-doped thin films. Structural quality was verified with X-ray diffraction (XRD), and optical properties were investigated using room temperature photoluminescence (PL) and optical transmission measurements. Properties of ZnO:TM bulk crystals and thin films are compared and used to discuss possible origins of ferromagnetism in these materials.

scholarly journals Study of the Magnetic Field of the Galaxy using Correlation Functions of the Intensity of Synchrotron Background Radio Emission

1996 ◽  
Vol 169 ◽  
pp. 615-616
Author(s):  
V.R. Shoutenkov
Keyword(s):  
Magnetic Field ◽  
Radio Emission ◽  
Correlation Functions ◽  
Theoretical Calculations ◽  
Angular Separation ◽  
Field Studies ◽  
Position Angle ◽  
The Galaxy ◽  
Image Position ◽  
The Magnetic Field

The possibility to study magnetic field of the Galaxy calculating correlation or structure functions of synchrotron background radio emission have been known long ago (Kaplan and Pikel'ner (1963); Getmantsev (1958)). But this method had not been as popular as other methods of magnetic field studies. However theoretical calculations made by Chibisov and Ptuskin (1981) showed that correlation functions of intensity of synchrotron background radio emission can give a lot of valuable information about galactic magnetic fields because of the intensity of synchrotron background radio emission depends on H⊥. According to this theory correlation C(θ, φ) and structure S(θ, φ) functions of intensity, as functions of angular separation θ between two lines of sight and position angle φ on the sky between this two lines of sight, can be presented as a sum of isotropic (not dependent from angle φ) and anisotropic parts:

scholarly journals A model of the response of GMR of metallic multilayers to external magnetic field

2015 ◽  
Vol 33 (4) ◽  
pp. 835-840
Author(s):  
J.I. Uba ◽  
A.J. Ekpunobi ◽  
P.I. Ekwo
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Giant Magnetoresistance ◽  
Ion Beam ◽  
Interface Roughness ◽  
Total Density ◽  
Metallic Multilayers ◽  
Interface Quality ◽  
Qualitative Measure

AbstractIt has not been possible to transform resistivity models in terms of magnetic field in order to account for variation of giant magnetoresistance (GMR) with external magnetic field, which would have led to determination of material properties. This problem is approached mathematically via variation calculus to arrive at an exponential function that fits observed GMR values. Using this model in free electron approximation, the mean Fermi vector, susceptibility and total density of states of a number of metallic multilayers are determined from their reported GMR values. Susceptibility is found to depend on interface roughness and antiferromagnetic (AF) coupling; thus, it gives qualitative measure of interface quality and AF coupling. Comparison of susceptibilities and GMRs of electrodeposited and ion beam sputtered Co/Cu structures shows that a rough interface suppresses GMR in the former but enhances it in the latter.

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