Simultaneous probing of exchange and spin-orbit interaction in spin polarized low energy electron diffraction from magnetic surfaces

Alvarado, S. F.; Feder, R.; Hopster, H.; Ciccacci, Franco; Pleyer, H.

doi:10.1007/bf01314748

Cited by 61 publications

(13 citation statements)

References 10 publications

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“…In electron scattering it has been shown that it is possible to separate the polarization effects by adding the polarized spectra in different ways. 52 For core level photoemission excited by circularly polarized light an analogous procedure was suggested. 30,42 If majority is added to majority, and minority to minority, then the effect of reversing the magnetization is canceled.…”

Section: Spin-resolved Magnetic Dichroismmentioning

confidence: 97%

Magnetic linear dichroism in spin-resolved Fe 2pphotoemission

et al. 1996

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Linear magnetic dichroism is studied for the Fe 2 p level by angle-and spin-resolved photoemission with high energy resolution. The dichroism occurs in angle-resolved experiments for a geometry as in the transverse magneto-optic Kerr effect, i.e., on reversal of sample magnetization in the direction normal to the plane defined by light polarization and electron emission. The large spin-orbit splitting allows us to investigate the jϭ1/2 and jϭ3/2 states separately. Spin analysis allows differentiation between polarization effects related to exchange and spin-orbit interactions. The results are discussed in the framework of an atomic model, where the exchange interaction between the magnetic d shell and the core hole lifts the degeneracy of magnetic sublevels of the core hole spectrum. The model is able to explain the general trend in the spectra, but does not fully account for the observed shapes of the jϭ3/2 peaks. The analysis shows that the dichroism is governed by the spin polarization parameter which determines the spin-orbit-induced spin polarization. This shows that if there is a magnetic dichroism then there is a finite spin-orbit-induced spin polarization. The rich structures observed in our complete experiment are evidence for the influence of many-electron effects in the Fe 2p spectrum.

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Section: Spin-resolved Magnetic Dichroismmentioning

confidence: 97%

Magnetic linear dichroism in spin-resolved Fe 2pphotoemission

et al. 1996

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“…Both spin orbit and exchange interaction can in general contribute to spin dependent scattering, 2 as has been experimentally demonstrated in the early 1980's by spin polarized low energy electron diffraction ͑LEED͒ studies. 15 It turns out that in ferromagnets with a large magnetic moment, such as Fe, the spin-orbit term is much smaller than the exchange one. 16,17 Only the latter was actually considered in more recent experiments on Fe͑001͒ and Fe͑110͒, 9,10 in which the spin dependent effects were ascribed to the exchange split band structure.…”

Section: Spin Dependent Scattering From Fe"001…-p"1؋1…omentioning

confidence: 99%

A novel electron spin-polarization detector with very large analyzing power

Bertacco

Onofrio

Ciccacci

1999

Review of Scientific Instruments

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Articles you may be interested inHigh-efficiency spin-resolved and spin-integrated electron detection: Parallel mounting on a hemispherical analyzer Rev. Sci. Instrum. 70, 4225 (1999); 10.1063/1.1150056 Two-dimensional toroidal electron analyzer for energy and angular dispersive measurements Rev.A new compact 60 kV Mott polarimeter for spin polarized electron spectroscopy Rev.The low energy electron reflectivity from a magnetic surface depends on the relative orientation between the electron spin and the sample magnetization. This effect has been exploited for realizing a new electron spin polarization detector. As a scattering surface we have used a well ordered Fe(001)-p(1ϫ1)O surface, which is stable against surface contamination and gives rise to very large spin dependent effects. We describe in detail the preparation in vacuum of such a target surface and show that it can be transferred in a separate system, without performance losses. The analyzing power S of the detector is given by the relative variation of its response when the target magnetization is reversed. We find extremely large S values for electrons reflected at 3-6 eV kinetic energy, with maximum above 45%, i.e., roughly 3 times better than other polarimeters presently used.

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“…10 ' 11 The Gd films were grown epitaxially on a single-crystal W(110) substrate. During evaporation the pressure remained below 2x 10~9 Torr.…”

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confidence: 99%

Observation of Surface-Enhanced Magnetic Order and Magnetic Surface Reconstruction on Gd(0001)

et al. 1985

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Epitaxial Gd(0001) has been investigated with spin-polarized low-energy-electron diffraction and the magneto-optic Kerr effect. The ferromagnetic critical temperature of the surface layer is found to lie up to 22 K above the bulk Curie point, demonstrating the existence of surface-enhanced magnetic order. Furthermore, spin-resolved photoemission spectroscopy reveals that the 4/ spins of the surface are not ferromagnetically coupled to the bulk moments.The concept of universality in the field of phase transitions has stimulated renewed interest for this mature field of solid state physics, because a variety of apparently very different phenomena can be described by the same theoretical principles. In this sense, for example, presetting criticality and pure surface-enhanced transitions are essentially the same phenomenon. 1 On the other hand, advances in experimental techniques today allow the crosschecking of such far-reaching predictions. Magnetic systems as model systems have always been appealing to experimentalists and theorists. Recently systems with free surfaces have been investigated extensively both analytically 2 " 4 and by Monte Carlo simulations. 5 For systems exhibiting a continuous bulk phase transition the critical behavior is found to be related to the ratio of J\/Jb of the parallel coupling Ji between surface spins in the top layer and that J b between bulk spins. For values of J x below a certain critical value J Xc the surface and the bulk will have the same critical temperature, while for J x > J Xc a pure "surface transition" has been predicted to occur. In such a case the surface spins undergo a critical ordering transition in the presence of disordered bulk spins. 5 One purpose of this Letter is to report the first direct observation of such a critical surface transition on epitaxial Gd(0001) by means of the surface-sensitive technique of spin-polarized low-energy-electron diffraction (SPLEED). For an in situ comparison with the corresponding bulk transition the magneto-optical Kerr effect was used. An interaction which is not included in the above model is that case when the perpendicular coupling between the topmost surface layer and the layer(s) below is different from J b . It is a further goal of this paper to investigate this question by means of spin-polarized photoemission. In fact, we find for the first time that the Af spins of the surface atoms of Gd(0001) undergo a so-called "magnetic surface reconstruction." 6 This observation has become possible by our making use of the surface-induced binding-energy shift of the 4/levels. 7 " 9The SPLEED technique as well as the spin-,

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Simultaneous probing of exchange and spin-orbit interaction in spin polarized low energy electron diffraction from magnetic surfaces

Cited by 61 publications

References 10 publications

Magnetic linear dichroism in spin-resolved Fe 2pphotoemission

Magnetic linear dichroism in spin-resolved Fe 2pphotoemission

A novel electron spin-polarization detector with very large analyzing power

Observation of Surface-Enhanced Magnetic Order and Magnetic Surface Reconstruction on Gd(0001)

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