Magneto-Optical Spectroscopy of RE/TM Alloys and TM/CO Multilayers

1991 ◽  
Vol 232 ◽  
Author(s):  
D. Weller ◽  
W. Rcim
Keyword(s):  
Transition Metal ◽  
Optical Spectroscopy ◽  
Kerr Effect ◽  
Near Infrared ◽  
Magnetic Transition ◽  
Metallic Multilayers ◽  
Kerr Rotation ◽  
X Ray ◽  
Order Of Magnitude ◽  
Magneto Optic

ABSTRACTThis paper reviews on magneto-optical spectroscopy of alloys, metallic multilayers and interference enhancement structures for magneto-optic (MO) recording. Mainly rare earth transition metal (RE-TM) alloys and Co/transition metal (Co/X) multilayers will be discussed. The read out performance in MO write/read tests is given by tile reflectivity and Kerr rotation strongly depends on the wavelength. While the magneto-optical transitions in the near infrared (IR:≈820nm) are dominated by tile 3d magnetic transition metals Fe and Co, the properties in the ultraviolet (UV: <400nm) can be dominated by either rare earths like Nd or Pr in RE-TM alloys or by exchange polarized Pt or Pd in Co/X multilayers and their respective alloys.In an attempt to correlate the magneto-optic Kerr effect to electronic properties we have systematically investigated alloys and multilayers with x-ray photoemission (XPS) and polar magneto-optical Kerr spectroscopy (0.5–5.3eV range). It is found that electronic 4f levels in Nd or Pr contribute to the Kerr elffct via Γ→, d transitions in the order of 0.3°. Exchange polarized Pd and Pt in Co/X multilayers give rise to a room temperature Kerr rotation in the same order of magnitude via excitations of the 4d and 5d bands, respectively. These effects clearly depend on film compositions and thickness ratios.,

Observation of a giant Kerr rotation in a ferromagnetic transition metal byM-edge resonant magneto-optic Kerr effect

2014 ◽  
Vol 89 (6) ◽  
Author(s):  
Sh. Yamamoto ◽  
M. Taguchi ◽  
M. Fujisawa ◽  
R. Hobara ◽  
S. Yamamoto ◽  
...  
Keyword(s):  
Transition Metal ◽  
Kerr Effect ◽  
Ferromagnetic Transition ◽  
Kerr Rotation ◽  
Magneto Optic

Amorphous Transition Metal-Rare Earth Alloy Films for Magneto-Optic Recording

1986 ◽  
Vol 80 ◽  
Author(s):  
Fred E. Luborsky
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Perpendicular Magnetic Anisotropy ◽  
Anisotropy Constant ◽  
Environmental Stability ◽  
Large Temperature ◽  
Kerr Rotation ◽  
Rare Earth Alloy ◽  
History Of ◽  
Magneto Optic

AbstractThis paper reviews the history of the development of films for use in magneto-optic recording. A discussion of why these early attempts with films of MnBi and Europium compounds were abandoned is given. The current work on amorphous transition metal-rare earth alloys is then reviewed. The origins of the necessary perpendicular magnetic anisotropy are discussed. The ideal combination of properties desired are: a high room temperature coercivity, a large temperature coefficient of coercivity, a large perpendicular anisotropy constant, large Ms, thermal and environmental stability, and, depending on whether a reflection or absorption mode of operation will be used, a large Kerr rotation with large reflectivity or a large Faraday rotation with a small specific absorption. These factors, their control, bow they influence the recording performance and the limits on performance of these amorphous films are discussed.

scholarly journals Evidence for magnetic activity at starbirth: a powerful X-ray flare from the Class 0 protostar HOPS 383

2020 ◽  
Vol 638 ◽  
pp. L4 ◽  
Author(s):  
Nicolas Grosso ◽  
Kenji Hamaguchi ◽  
David A. Principe ◽  
Joel H. Kastner
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Direct Proof ◽  
Magnetic Activity ◽  
Evolutionary Stage ◽  
X Rays ◽  
X Ray ◽  
Order Of Magnitude ◽  
Solar Type ◽  
Bona Fide

Context. Class 0 protostars represent the earliest evolutionary stage of solar-type stars, during which the majority of the system mass resides in an infalling envelope of gas and dust and is not yet in the central, nascent star. Although X-rays are a key signature of magnetic activity in more evolved protostars and young stars, whether such magnetic activity is present at the Class 0 stage is still debated. Aims. We aim to detect a bona fide Class 0 protostar in X-rays. Methods. We observed HOPS 383 in 2017 December in X-rays with the Chandra X-ray Observatory (∼84 ks) and in near-infrared imaging with the Southern Astrophysical Research telescope. Results. HOPS 383 was detected in X-rays during a powerful flare. This hard (E >  2 keV) X-ray counterpart was spatially coincident with the northwest 4 cm component of HOPS 383, which would be the base of the radio thermal jet launched by HOPS 383. The flare duration was ∼3.3 h; at the peak, the X-ray luminosity reached ∼4 × 1031 erg s−1 in the 2−8 keV energy band, a level at least an order of magnitude larger than that of the undetected quiescent emission from HOPS 383. The X-ray flare spectrum is highly absorbed (NH ∼ 7 × 1023 cm−2), and it displays a 6.4 keV emission line with an equivalent width of ∼1.1 keV, arising from neutral or low-ionization iron. Conclusions. The detection of a powerful X-ray flare from HOPS 383 constitutes direct proof that magnetic activity can be present at the earliest formative stages of solar-type stars.

scholarly journals Unravelling strong electronic interlayer and intralayer correlations in a transition metal dichalcogenide

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
T. J. Whitcher ◽  
Angga Dito Fauzi ◽  
D. Caozheng ◽  
X. Chi ◽  
A. Syahroni ◽  
...  
Keyword(s):  
Transition Metal ◽  
Near Infrared ◽  
Theoretical Calculations ◽  
High Energy ◽  
Low Energy ◽  
Great Effort ◽  
Energy Bands ◽  
Electronic Correlations ◽  
X Ray ◽  
Wide Range

AbstractElectronic correlations play important roles in driving exotic phenomena in condensed matter physics. They determine low-energy properties through high-energy bands well-beyond optics. Great effort has been made to understand low-energy excitations such as low-energy excitons in transition metal dichalcogenides (TMDCs), however their high-energy bands and interlayer correlation remain mysteries. Herewith, by measuring temperature- and polarization-dependent complex dielectric and loss functions of bulk molybdenum disulphide from near-infrared to soft X-ray, supported with theoretical calculations, we discover unconventional soft X-ray correlated-plasmons with low-loss, and electronic transitions that reduce dimensionality and increase correlations, accompanied with significantly modified low-energy excitons. At room temperature, interlayer electronic correlations, together with the intralayer correlations in the c-axis, are surprisingly strong, yielding a three-dimensional-like system. Upon cooling, wide-range spectral-weight transfer occurs across a few tens of eV and in-plane p–d hybridizations become enhanced, revealing strong Coulomb correlations and electronic anisotropy, yielding a two-dimensional-like system. Our result shows the importance of strong electronic, interlayer and intralayer correlations in determining electronic structure and opens up applications of utilizing TMDCs on plasmonic nanolithrography.

scholarly journals MAGNETO-OPTIC PROPERTIES AND OXIDATION/REDUCTION OF ULTRATHIN MAGNETIC FILMS: FE FILMS ON Pt(111)

2017 ◽  
Vol 24 (1&2) ◽  
pp. 107-117
Author(s):  
T.-U. Nahm
Keyword(s):  
Photoelectron Spectroscopy ◽  
Kerr Effect ◽  
Magnetic Films ◽  
No Oxidation ◽  
X Ray ◽  
Post Annealing ◽  
Oxidation Reduction ◽  
Iron Oxide Films ◽  
Magneto Optic

We have investigated magneto-optic properties of ultrathin Fe films grown on Pt(111) surfaces by using the in situ surface magneto-optic Kerr effect (SMOKE) and X-ray photoelectron spectroscopy (XPS). SMOKE measurements show that the Fe layers are not ferromagnetic when the film is thinner than approximately 4.5 MLs (monolayers), but the in-plane magnetization is present for a 4.1 ML Fe film on Pt(111) annealed at 550 K. Upon post-annealing at 770 K, a 9.2 ML Fe film does not show any Kerr signal, while a 6.3 ML Fe film has the in-plane Kerr signal with increased coercivity. The oxidation and reduction of ultrathin Fe films have also been studied by using XPS. Upon an oxygen exposure of 300 Langmuir at a film temperature of 873 K, the Fe layers were mostly oxidized as Fe3O4. When the Fe films were exposed to the same amount of oxygen at room temperature, a partial oxidation as Fe3O4 was observed for a 3 ML Fe film, while there was no oxidation for a 2 ML Fe film. On heating the 873 K oxidized films, Fe3O4O was reduced to FeO, and even the decomposition was observed. Underlying reasons for these chemical changes of Fe and iron-oxide films are discussed.

scholarly journals X-ray magneto-optic Kerr effect studies of spring magnet heterostructures

2001 ◽  
Vol 467-468 ◽  
pp. 1396-1403 ◽  
Author(s):  
J.B. Kortright ◽  
Sang-Koog Kim ◽  
E.E. Fullerton ◽  
J.S. Jiang ◽  
S.D. Bader
Keyword(s):  
Kerr Effect ◽  
X Ray ◽  
Magneto Optic

scholarly journals Determination of the magnetization profile of Co/Mg periodic multilayers by magneto-optic Kerr effect and X-ray magnetic resonant reflectivity

2013 ◽  
Vol 417 ◽  
pp. 012025
Author(s):  
P Jonnard ◽  
K Le Guen ◽  
J-M André ◽  
R Delaunay ◽  
N Mahne ◽  
...  
Keyword(s):  
Kerr Effect ◽  
X Ray ◽  
Magneto Optic

Wettability manipulation of magnetic transition metal nanorod arrays by X-ray irradiation

2015 ◽  
Vol 9 (3) ◽  
pp. 311-315 ◽  
Author(s):  
Qian Xie ◽  
Weipeng Wang ◽  
Zheng Xie ◽  
Shuang Shuang ◽  
Zhengcao Li ◽  
...  
Keyword(s):  
Transition Metal ◽  
Magnetic Transition ◽  
Nanorod Arrays ◽  
X Ray
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