Electronic structure of EuO spin filter tunnel contacts directly on silicon

Abstract

We present an electronic structure study of a magnetic oxide/ semiconductor model system, EuO on silicon, which is dedicated for efficient spin injection and spin detection in silicon‐based spintronics devices. A combined electronic structure analysis of Eu core levels and valence bands using hard X‐ray photoemission spectroscopy was performed to quantify the nearly ideal stoichiometry of EuO “spin filter” tunnel barriers directly on silicon, and the absence of silicon oxide at the EuO/Si interface. These results provide evidence for the successful integration of a magnetic oxide tunnel barrier with silicon, paving the way for the future integration of magnetic oxides into functional spintronics devices. Hard X‐ray photoemission spectroscopy of an Al/EuO/Si heterostructure probing the buried EuO and EuO/Si interface. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Heteroepitaxy and ferromagnetism of EuO/MgO (001): A route towards combined spin- and symmetry-filter tunneling

“…Figure 3 depicts the Eu 4d and 3d 3/2 core-level spectra recorded at a photon energy of hν = 6 keV and T = 33 K. Both spectra show well-resolved final-state multiplets, which agree very well with photoemission multiplets of Eu 2+ ions from experimental studies of divalent Eu compounds 15,16 and theoretical multiplet calculations. 23,24 At the high-binding-energy side, smaller spectral contributions are observable, which are part of the complex Eu 2+ final-state multiplet and do not indicate any different EuO phases, e.g., Eu 3+ ions.…”

“…The major experimental difficulty relies in synthesizing the metastable oxide EuO in its stoichiometric ferromagnetic phase since off-stoichiometry precludes an epitaxial growth and also reduces ferromagnetic exchange in the ultrathin-film limit, which is, however, essential for efficient spin-filter tunneling. [13][14][15][16][17] In recent years, several growth studies on EuO thin films have been presented, in particular on stoichiometric EuO thin films grown coherently on perfectly lattice-matched yttriastabilized zirconia (YSZ) 14,18 and on different cubic oxides with only a few percent tensile lattice strain. 19,20 The system EuO/MgO (001), however, provides a large compressive lattice mismatch of m = (a MgO − a EuO )/a EuO = −18%.…”

Electrical detection of spin hyperpolarization in InP

“…[9][10][11] Tunnel spin injection of spin-pumped electrons into various ferromagnets (FM) was shown to be efficient in the case of GaAs: Isakovic et al, 12 Nakajima et al, 13 and Hirohata et al 14 used the so-called spin diode structures, which were theoretically described by Li. 15 The spin excitation of the "spin diodes" was based on photon irradiation through a GaAs/Schottky/FM stack 14,[16][17][18][19] of macroscopic extent.…”

Schaltbare Transparenz in hochgradig lumineszierenden dünnen Filmen der Raumnetzverbindung 3∞[EuIm2] abgeschieden durch Femto‐Laserablation

“…Unerwarteterweise wurden polykristalline [26] und intermetallischen Phasen [27,28] zeigen, dass Europium in der Tat zweiwertig in den Filmen vorliegt, mit einer geringfügigen Oberflächenoxidation zu Eu III , welche in ähnlicher Weise auch für EuO-Filme beobachtet wurde (Abbildung S3). [26] Zur [22] ).…”

“…[26] Zur [22] ). Die Schichtdicken der Filme, 100 bis 500 nm, wurden mit REM und kombinierter Rçntgenfluores-zenzspektroskopie bestimmt.…”