Photoemission study of Fermi surfaces of pseudomorphic Co, Ni, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Co</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ni</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mi>−</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>films on Cu(100)

Hochstrasser, M.; Gilman, N.; Willis, R. F.; Schumann, F. O.; Tobin, J. G.; Rotenberg, Eli

doi:10.1103/physrevb.60.17030

Cited by 13 publications

(4 citation statements)

References 27 publications

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“…These dispersions are plotted in Fig 1 . For an experimental and theoretical study of Co and Ni band structures that also discusses the nomenclature of the bands, see Ref. 20. The exciting laser pulse has a typical full-width at half-maximum of 50 fs, photon energy of 1.55 eV and the fluence is numerically adjusted to be in qualitative agreement with an estimate of the absorption and the observed magnetization quenching.…”

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confidence: 99%

Ultrafast demagnetization of ferromagnetic transition metals: The role of the Coulomb interaction

et al. 2009

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The Elliott-Yafet ͑EY͒ mechanism is arguably the most promising candidate to explain the light-induced ultrafast demagnetization dynamics in ferromagnetic transition metals on time scales on the order of 100 fs. So far, only electron-phonon ͑or impurity͒ scattering has been analyzed as the scattering process needed to account for the demagnetization. We show that an EY-like mechanism based on electron-electron scattering has the potential to explain time-resolved magneto-optical Kerr effect measurements on thin magnetic Co and Ni films, without reference to a "phononic spin bath." Current research in femtosecond magnetism is concerned with elucidating the fundamental mechanisms of lightinduced spin dynamics as well as searching for potential applications in data processing. 1-3 Despite important experimental studies employing various time-resolved techniques, no consensus on a microscopic understanding of ultrafast magnetization dynamics in ferromagnets has emerged. Rather, demagnetization dynamics is typically described in the framework of the phenomenological three-temperature model. In this model, temperatures are assigned to the electron, lattice, and spin "subsystems," and the exchange of energy ͑and spin͒ is driven by the temperature differences between the respective subsystems. Although the threetemperature model provides an intuitive picture of demagnetization, its relation to the microscopic dynamics behind the demagnetization is still an active field of research.The most popular candidate 4 for the microscopic process behind light-induced ultrafast demagnetization is a mechanism of the Elliott-Yafet ͑EY͒ type. 5 In the EY mechanism, the demagnetization arises because, in the presence of the spin-orbit ͑SO͒ interaction, spin is not a good quantum number, so that any momentum-dependent scattering mechanism changes the spin admixture when an electron is scattered from state ͉k ជ ͘ to ͉k ជ + q ជ͘. So far, the scattering processes responsible for the EY mechanism have been assumed to be ͑quasi͒elastic electron-phonon and electron-defect scattering in several theoretical and experimental studies. 4,6-9 Unlike these papers, we analyze the ultrafast demagnetization in ferromagnetic metals due to an EY-like mechanism based exclusively on electron-electron Coulomb scattering. This scattering mechanism is not ͑quasi͒elastic, so that the available phase space for transitions from minority to majority bands is much larger than for electron-phonon scattering, which can only cause transitions near points in the Brillouin zone where the bands are energetically close. As a proof of principle for the importance of electron-electron scattering for the demagnetization, we demonstrate quantitative agreement for the demagnetization time and magnetization quenching between time-resolved magneto-optical Kerr effect ͑TR-MOKE͒ measurements on Co and Ni, and numerical results based on the EY mechanism due to electron-electron scattering.To resolve the electronic demagnetization dynamics on ultrafast time scales, we calculate the...

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confidence: 99%

Ultrafast demagnetization of ferromagnetic transition metals: The role of the Coulomb interaction

et al. 2009

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“…From previous work, the single crystals are known to provide sharper features near E F than epitaxial thin films. 10,14,15 The single crystals were prepared by annealing in 100 Torr H 2 for several days to remove bulk impurities with temperature ramping from 500°C to 850°C, the removal of segregated impurities by repolishing, electropolishing in a chromic acid solution, 16 and sputter annealing up to 800°C. For the Ni 0.96 Cu 0.04 sample a "diffusion method" was used 14 in which approximately 9 Å of Cu was deposited by MBE and then the sample annealed above the 500°C Ni bulk diffusion temperature.…”

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confidence: 99%

“…It is therefore expected that dilute alloying of the transition metals, particularly while maintaining epitaxial thin film structures, 10,11 should allow us to tune the separation of d levels and thereby to tune the Stoner gap. This in turn allows us to select the degree of spin-flip scattering, for example, that produced by thermal excitation.…”

Section: Fcc Bandstructurementioning

confidence: 99%

Tuning the spin-flip gap in transition-metal magnets by alloying

et al. 2005

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We report angle-resolved photoemission measurements of the effects of alloying on the spin-polarized electronic states of ferromagnetic transition metals. We observe that the minimum energy for spin-flip scattering of d electrons ͑the so-called "Stoner gap" in itinerant ferromagnets͒ is governed by the upper limit of the majority d bands. This Stoner gap can be tuned by alloying, which correspondingly alters the polarization of spin currents and lifetime of spin states in designer magnetic alloys for spintronic devices.

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“…1 These considerations as well as an intrinsic interest in understanding magnetic phenomena in general have motivated numerous theoretical and experimental investigations of Ni and its alloys. [2][3][4][5][6][7][8][9][10] With this backdrop in mind, our purpose in this article is to confront first-principles theoretical predictions of the spinresolved photointensities in Ni͑100͒ with the corresponding experimental measurements. Specifically, we consider the very recent high-resolution angle-resolved photoemission spectroscopy͑ARPES͒ study of Ref.…”

Section: Introductionmentioning

confidence: 99%

High-resolution angle-resolved photoemission spectra from Ni(100): Matrix element effects and spin-resolved initial and final state bands

2002

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We have carried out extensive one-and three-step angle-resolved photoemission spectroscopy ͑ARPES͒ intensity computations on Ni͑100͒ within the band theory framework based on the local spin-density approximation. The results show a good overall level of accord with the recent high-resolution ARPES experiments on Ni͑100͒ which probe the majority-and minority-spin ⌺ 1 band along the ⌫-K direction near the Fermi energy (E F ), uncertainties inherent in our first-principles approach notwithstanding. The k ʈ and energy dependencies of various spectral features are delineated in terms of the interplay between changes in the initial-and finalstate bands and the associated transition matrix elements. The remarkable decrease observed with decreasing k ʈ in the ARPES intensity of the majority-spin ⌺ 1 band as it disperses below the E F as well as an enhanced spin polarization of the photoemitted electrons from the E F is shown to arise from the presence of a band gap in the final-state spectrum.

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Photoemission study of Fermi surfaces of pseudomorphic Co, Ni, andCoxNi1−xfilms on Cu(100)

Cited by 13 publications

References 27 publications

Ultrafast demagnetization of ferromagnetic transition metals: The role of the Coulomb interaction

Ultrafast demagnetization of ferromagnetic transition metals: The role of the Coulomb interaction

Tuning the spin-flip gap in transition-metal magnets by alloying

High-resolution angle-resolved photoemission spectra from Ni(100): Matrix element effects and spin-resolved initial and final state bands

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