Angular Resolved X-ray Photoelectron Spectroscopy Research Articles

Titanium infiltration into ultrathin PMMA brushes

Vapor phase infiltration (VPI) is a bottom-up process that involves the infiltration of polymers, often using atomic layer deposition compatible precursors. By exposing a polymer to an organo-metallic precursor, area selective material formation is achieved where the precursor reacts with regions covered by an infiltration-receptive polymer brush. Combining receptive and rejecting polymers that have the capability of forming complex nanopatterns could potentially allow for the creation of nanofeatures, offering a route to area selective deposition. This work is concerned with the creation and characterization of titanium-infiltrated films with a VPI process. Thin films of poly(methyl methacrylate) (PMMA) were infused with titanium isopropoxide and subsequently analyzed with angular resolved x-ray photoelectron spectroscopy. All XPS analysis and VPI treatments were completed without breaking vacuum in an integrated ultrahigh vacuum setup, with O 1s, C 1s, Ti 2p, and Si 2p core levels revealing the successful incorporation of titanium into the polymer. Grazing angle Fourier-transform infrared spectroscopy demonstrates the breaking of carbon–oxygen double bonds within the PMMA structure due to titanium incorporation.

Influences of substrate temperatures on etch rates of PECVD-SiN thin films with a CF4/H2 plasma

The dependence of substrate temperatures (50 to −20 °C) on etch rate in two kinds of PECVD SiN films were investigated by a CF4/H2 mixture plasma. The XRR and XPS results indicate that the chemical composition and film density were almost identical for the films. The FTIR shows that the ratio of NH and SiH groups were found to be significantly different in the SiN films. The NH rich films exhibited a lower etch rate at −20 °C than that observed at room temperature or higher, whereas the SiH rich films showed a higher etch rate at −20 °C. We found that the fluorocarbon thickness was thicker in the SiH rich samples than NH rich samples. The fact suggests that hydrogen originated from the broken SiH bonds enhanced the polymerization, which causes the decrease of etch rate. A thinner fluorocarbon thickness was found in the SiH rich samples at low temperature, which results in the higher etch rate. Angular-resolved XPS indicates that NH bonding formed easier on film surface at −20 °C. These results indicate that the bonding structure and substrate temperature affected the fluorocarbon thickness, fluorine reaction probability and hydrogen dissociation during the SiN etching.

Oxidation Process in Ge-Rich GeSbTe Alloy for Phase-Change Memory: Mechanism, Kinetic and N-Doping Influence

Phase-change materials (PCMs) based on GeSbTe alloys are well known and widely used in optical storage devices. The recent progress in scaling and material engineering made PCMs also promising candidates for high-speed non-volatile memory applications [1]. Indeed, Phase-Change Memory (or PCM) devices feature high writing and reading speed and compatibility with high working and storage temperatures.Ge-rich GeSbTe is a promising material for embedded applications requiring high data stability at high temperature, thanks to its higher crystallization temperature wrt standard PCMs such as Ge2Sb2Te5 [2-3]. Moreover, N doping in Ge-rich GeSbTe was also introduced in order to stabilize even more the material at high temperature, and improve its programming performances [4-5]. However, fabrication steps like etching or stripping that imply an exposure of the PCMs to air, could affect the material properties and the final device performance [6]. It is known that Ge is particularly sensitive to oxidation, and this makes even more important to well understand and study such phenomena in Ge-rich GeSbTe. Recent observations already reported the appearing of segregation mechanisms due to surface oxidation in Ge2Sb2Te5 and Ge-rich GeSbTe [7]. Such material degradation could significantly affect the final device performance and the electrical parameters variability. Therefore, the understanding of the physics of these mechanisms become fundamental for improving the fabrication steps for future further improvements of the device (e.g. new barriers, new etching strategies, etc.).This study focuses on the oxidation mechanism and on its kinetic in Ge-rich GeSbTe, and how it is influenced by N doping. We analyzed the oxidation in amorphous and crystalline samples, at room temperature and after annealing of increasing duration at high temperature in order to accelerate oxidation process. Using surface characterization by pARXPS (parallel angular resolved XPS), we monitor with precision the evolution in time of the oxide thickness (figure 1) and of the composition of different N-doped Ge-rich GeSbTe samples (figure 2). We report the evolution of our samples along more than one year, showing a double steps oxidation mechanism, with a kinetic strongly dependent on N content. Oxidation speed and thickness are then correlated with N content, leading to an analytical model that is in agreement with all the data acquired (figure 3), and that allows to describe the ongoing oxidation and segregation phenomena. TEM images completed by EDX analyses (figure 4) are here shown to support our findings.In this work, we present the study of the oxidation mechanism and kinetic in N-doped Ge-rich GeSbTe materials by pARXPS, TEM and EDX analyses. We propose an analytical model for the oxidation kinetic based on our data, highlighting the strong impact of N doping concentration on the parameters of our model. [1] G. Navarro et al., “Phase-Change Memory: Performance, Roles and Challenges,” in 2018 IEEE International Memory Workshop (IMW), Kyoto, 2018, pp. 1–4, doi: 10.1109/IMW.2018.8388845. [2] P. Zuliani et al., "Overcoming Temperature Limitations in Phase Change Memories With Optimized GexSbyTez" in IEEE Transactions on Electron Devices, vol. 60, no. 12, pp. 4020-4026, Dec. 2013. [3] J. Kluge et al., “High Operating Temperature Reliability of Optimized Ge-Rich GST Wall PCM Devices,” 2016, pp. 1–4, doi: 10.1109/IMW.2016.7495273 [4] G. Navarro et al., “Trade-off between SET and data retention performance thanks to innovative materials for phase-change memory,” 2013, pp. 21.5.1-21.5.4, doi: 10.1109/IEDM.2013.6724678. [5] A. Kiouseloglou et al., “A Novel Programming Technique to Boost Low-Resistance State Performance in Ge-Rich GST Phase Change Memory,” IEEE Transactions on Electron Devices, vol. 61, no. 5, pp. 1246–1254, May 2014, doi: 10.1109/TED.2014.2310497. [6] P. Noé, C. Sabbione, N. Bernier, N. Castellani, F. Fillot, and F. Hippert, “Impact of interfaces on scenario of crystallization of phase change materials,” Acta Materialia, vol. 110, pp. 142–148, May 2016, doi: 10.1016/j.actamat.2016.03.022. [7] M. Agati, C. Gay, D. Benoit, and A. Claverie, “Effects of surface oxidation on the crystallization characteristics of Ge-rich Ge-Sb-Te alloys thin films,” Applied Surface Science, vol. 518, p. 146227, Jul. 2020, doi: 10.1016/j.apsusc.2020.146227. Figure 1

Photogenerated charge collection on diamond electrodes with covalently linked chromophore monolayers

Encouraged by its rich surface chemistry and excellent electrochemical properties, boron-doped nanocrystalline diamond (B:NCD) is a promising p-type photoelectrode in dye-sensitized solar cells. One method of diamond surface functionalization using stable carbon-carbon bonds involves the electrochemical grafting of diazonium salts. However, this method typically leads to multilayers that may complicate the transport of photogenerated charges. Here, we establish functionalization of B:NCD electrodes by a monolayer of ethynylphenyl molecules using sterically hindered 4-(trimethylsilyl)ethynylbenzenediazonium tetrafluoroborate. Both the density and structural orientation of the grafted layer are investigated by angular resolved X-ray photoelectron spectroscopy, confirming the presence of covalently grafted monolayers. After removal of the trimethylsilyl protective groups, the resulting ethynyl functionalities are employed to immobilize organic donor-acceptor chromophores via Sonogashira cross-coupling reactions. Homogenous surface coverage is achieved even on the B:NCD electrode. Atomic scale DFT computing reveals that for the chromophore with the strongest acceptor unit, efficient charge separation of 20 Å is obtained where photogenerated holes move directly into diamond. Yet, photocurrent and photovoltage measurements suggest competitive electron recombination to the diamond electrode via the redox electrolyte. Correlation between the density of the molecular layer and photocurrents/photovoltage provides better understanding of the charge generation and recombination pathways in diamond-organic photoelectrochemical cells.

Evolution of LiFePO4 thin films interphase with electrolyte

Many parameters may control the growth and the characteristics of the interphase, such as surface structure and morphology, structural defects, grain boundaries, surface reactions, etc. However, polycrystalline surfaces contain these parameters simultaneously, resulting in a quite complicated system to study. Working with model electrode surfaces using crystallographically oriented crystalline thin films appears as a novel and unique approach to understand contributions of preferential orientation and rugosity of the surface. In order to rebuild the interphase architecture along electrochemical cycling, LiFePO4 epitaxial films offering ideal 2D (100) interfaces are here investigated through the use of non-destructive depth profiling by Angular Resolved X-ray Photoelectron Spectroscopy (ARXPS). The composition and structure of the interphase is then monitored upon cycling for samples stopped at the end of charge and discharge for various numbers of cycles, and discussed in the light of combined XPS and X-ray reflectivity (XRR) measurements. Such an approach allows describing the interphase evolution on a specific model LiFePO4 crystallographic orientation and helps understanding the nature and evolution of the LiFePO4/electrolyte interphase forming on the surface of LiFePO4 poly-crystalline powder.

Effects of oxide replacement with fluoride at the CoFeB interface on interface magnetic anisotropy and its voltage control

In this paper we report results of improving Co60Fe20B20 interface perpendicular magnetic anisotropy (PMA) by replacing neighbor oxide layer with fluoride one. We expected that fluorine as element with higher than oxide electronegativity could more effectively attract electrons from out-of-plane d orbitals of ferromagnetic, increasing role of in-plane orbitals. By this we wanted to increase PMA and its response to applied voltage bias. Polar magneto-optic Kerr effect measurement show decreasing of out-of-plane magnetic field needed to change magnetization to perpendicular in stacks with oxygen replaced by fluorine as well as increasing of coefficient of response to applied voltage α from < 10 fJ/Vm for CoFeB/Al2O3 interface to 20 fJ/Vm for CoFeB/AlF3/Al2O3 and 22 fJ/Vm for CoFeB/MgF2 stacks. Direct chemical interaction of Co with F was confirmed by x-ray photoelectron spectroscopy (XPS) measurement of Co2p core level region. Moreover angular-resolved XPS showed that F tends to stay at CoFeB interface rather than diffuse out of it.

Intermixing and thermal oxidation of ZrO2 thin films grown on a-Si, SiN, and SiO2 by metallic and oxidic mode magnetron sputtering

The initial growth of DC sputtered ZrO2 on top of a-Si, SiN, and SiO2 layers has been studied by in vacuo high-sensitivity low energy ion scattering for two gas deposition conditions with different oxygen contents (high-O and low-O conditions). This unique surface sensitive technique allowed the determination of surface composition and thicknesses required to close the ZrO2 layer on all three substrates for both conditions. The ZrO2 layer closes similarly on all substrates due to more favorable enthalpies of formation for ZrO2 and ZrSiO4, resulting in passivation of the Si from the substrate. However, this layer closes at about half of the thickness (∼1.7 nm) for low-O conditions due to less oxidative conditions and less energetic particles arriving at the sample, which leads to less intermixing via silicate formation. In contrast, for high-O conditions, there is more ZrSiO4 and/or SiOx formation, giving more intermixing (∼3.4 nm). In vacuo X-ray photoelectron spectroscopy (XPS) measurements revealed similar stoichiometric ZrO2 layers deposited by both conditions and a higher interaction of the ZrO2 layer with the underlying a-Si for high-O conditions. In addition, oxygen diffusion through low-O ZrO2 films on a-Si has been investigated by ex situ angular-resolved XPS of samples annealed in atmospheric oxygen. For temperatures below 400 °C, no additional oxidation of the underlying a-Si was observed. This, together with the amorphous nature and smoothness of these samples, makes ZrO2 a good candidate as an oxidation protective layer on top of a-Si.

Co-Ir interface alloying induced by thermal annealing

Using angular resolved X-ray Photoelectron Spectroscopy (XPS), Magneto Optic Kerr Effect (MOKE) and X-ray Absorption Spectroscopy (XAS), we characterize the structural and magnetic evolution upon annealing of two thin Co films (8 and 9 Monolayers) deposited on Ir(111). The XAS data collected in the near Co K edge region (XANES), interpreted with ab-initio simulations, show that intermixing takes place at the Co-Ir interface. Using a linear combination analysis, we follow the intermixing during the thermally driven diffusion process. At 500 °C, the interface between Co and Ir(111) roughens slightly, but no alloy formation is detected. At 600 °C, the Co film loses integrity and MOKE data show a rearrangement of the magnetic domains. Annealing to higher temperatures results in CoxIr1 − x alloy formation and Ir segregation on the surface.

Interpretation of X-ray photoelectron spectra of carbon-nitride thin films: New insights from in situ XPS

We report on angular-resolved x-ray photoelectron spectroscopy (XPS) studies of magnetron sputtered CNx thin films, first in situ (without air exposure), then after air exposure (for time periods ranging from minutes to several years), and finally after Ar ion etching using ion energies ranging from 500 eV to 4 keV. The as-deposited films typically exhibit two strong N1s peaks corresponding to pyridine-like, and graphite-like, at ∼398.2 eV and ∼400.7 eV, respectively. Comparison between in situ and air-exposed samples suggests that the peak component at ∼402–403 eV is due only to quaternary nitrogen and not oxidized nitrogen. Furthermore, peak components in the ∼399–400 eV range cannot only be ascribed to nitriles or pyrrolic nitrogen as is commonly done. We propose that it can also be due to a polarization shift in pyridinic N, induced by surface water or hydroxides. Argon ion etching readily removes surface oxygen, but results also in a strong preferential sputtering of nitrogen and can cause amorphization of the film surface. The best methods for evaluating and interpreting the CNx film structure and composition with ex-situ XPS are discussed.

Using neutral impact collision ion scattering spectroscopy and angular resolved X-ray photoelectron spectroscopy to analyze surface structure of surfactant solutions

In the present work, the surface structure of solutions of tetrabutylammonium iodide dissolved in formamide is in parallel analyzed by neutral impact collision ion scattering spectroscopy (NICISS) and angular resolved X-ray photoelectron spectroscopy (ARXPS). By NICISS, the concentration-depth profiles of the solute ions and solvent are achieved, whereas by ARXPS, those fraction-depth profiles are obtained. For the sake of convenient comparisons, the fraction-depth profiles are converted to concentration-depth profiles after the determination of the partial molar volume of the components. With those profiles, the surface structures of the solutions are mapped. The cations and anions distribute distinctly within the surface layer, indicating the complication of the surface structure of ionic surfactant solution. According to the definition of Gibbs dividing plane, the surface excesses of surfactant ions are determined. Those profiles and surface excesses obtained by two distinct methods are compared directly. The comparison shows good agreements in both items. The differences are also found during the comparison, and the causes are analyzed within the frame of the working mechanisms of those analytical techniques.

Quantification of deexcitation processes for analyzing liquid surfaces

In the last two decades the mathematical tools for quantitative data evaluation have been developed for several surface spectroscopic techniques like Angular Resolved X-ray Photoelectron Spectroscopy (ARXPS), Neutral Impact Collision Ion Scattering Spectroscopy (NICISS) and Metastable Induced Electron Spectroscopy (MIES). Provided that the experimental data are of good quality, quantitative data processing can add a lot to the information that can be gained from surface spectroscopy. We give a selection of references that contain information on these methods. The emphasis of this contribution aims at providing motivation to apply quantitative data evaluation by presenting a few examples. We try to demonstrate, that careful data evaluation may lead to interesting insight into basic concepts as well as to results that are useful for practical applications.

Interface and plasma damage analysis of PEALD TaCN deposited on HfO2 for advanced CMOS studied by angle resolved XPS and C–V

Plasma enhanced atomic layer deposition (PEALD) TaCN deposited on HfO2 was studied by X-ray photoelectron spectroscopy (XPS) to understand the reactions taking place at the interface and connect them with C–V electrical characteristics of MOS devices. Moreover, angular resolved XPS (AR-XPS) was used for composition depth profiling of TaCN/HfO2/SiO2/Si stacks. Clear oxidation of the metal electrode through TaO bonding formation and migration of N in the dielectric with HfN are shown. These modifications of chemical bonding give an insight on the electrical results. Low equivalent oxide thicknesses (EOT), as low as 0.89nm and current leakage improvement by more than 5 decades, are observed for deposition with low plasma power and can be related to HfN content in HfO2 layer. The increase of plasma power used for TaCN deposition results in densification of the layer and promotes the creation of TaC in TaCN material. However H2 plasma has an impact on HfO2 with a reduction and scattering of the measured current leak gain. TaCN/HfO2 interface is also impacted with further creation of TaOx, leading to an increase of EOT when plasma power is increased. Based on these findings, reaction mechanisms with the corresponding Gibbs free energy are proposed.

Determination of energy levels at the interface between O2 plasma treated ITO/P3HT : PCBM and PEDOT : PSS/P3HT : PCBM using angular-resolved x-ray and ultraviolet photoelectron spectroscopy

Interfacial energy alignments at the anode of solution processable organic photovoltaics are rarely studied. Here we use blended regio-regular poly(3-hexylthiophene) (P3HT) : phenyl-C61-butyric acid methyl ester (PCBM) deposited on top of O2 plasma cleaned indium tin oxide (ITO) and poly(3,4-ethylene-dioxythiophene) : polystyrene sulfonic acid (PEDOT : PSS) as a platform to obtain the interfacial energy alignment using angular-resolved x-ray and ultraviolet photoelectron spectroscopy. A strong downward vacuum level bending of 1.3 eV at the interface for plasma-ITO/P3HT : PCBM is observed. This results in an interfacial energetic barrier as high as 2.5 eV for holes and a reduction of barrier for electrons. This could be one of the contributing factors that result in lower device efficiency in O2 plasma-ITO/P3HT : PCBM compared to O2 plasma-ITO/PEDOT : PSS/P3HT : PCBM. The full interfacial energy diagram is determined for O2 plasma-ITO/P3HT : PCBM and PEDOT : PSS/P3HT : PCBM. Such methods can be extended to study various interfacial properties of solution processable organic semiconducting materials.

X-ray photoelectron spectroscopy analysis and band offset determination of CeO2deposited on epitaxial (100), (110), and (111)Ge

The oxidation states, interface, and band alignment properties of physical vapor deposited CeO2 films on epitaxial (100), (110), and (111)Ge were investigated by x-ray photoelectron spectroscopy (XPS). The cross-sectional transmission electron microscopy demonstrated the polycrystalline nature of the CeO2 film. XPS analysis showed multiple Ce3d and Ce4d oxidation states with a mixture of Ce3+ and Ce4+ components existing in CeO2. Angular resolved XPS investigations indicate that the CeO2 films mostly consist of Ce4+ oxidation states while the Ce3+ oxidation states are preferentially present near the surface. The CeO2/(100)Ge, CeO2/(110)Ge, and CeO2/(111)Ge structures showed almost identical valence band offset (VBO) values of 1.6, 1.5, and 1.6 eV, respectively, using XPS measurements from Ce3d core level (CL) peaks. These (VBO) values were also supported by XPS measurements from shallow Ce4d CL binding energy peaks. The conduction band offset values between CeO2/Ge were ∼1.3 eV using the measured optical bandgap of CeO2. The XPS spectral analysis of cerium oxidation states and the measured band offset parameters for carrier confinement would offer an important path for the future design of Ge-based metal-oxide semiconductor devices.

Diffusion of In and Ga in TiN/HfO2/InGaAs nanofilms

The structure of TiN/HfO2 nanofilms grown on InxGa1−xAs substrates was assessed through angular-resolved x-ray photoelectron spectroscopy. The quantitative analysis made possible determining the thickness and composition of the various layers constituting the nanofilms treated at different temperatures (un-annealed, 500 °C/120 s and 700 °C/10 s). The TiN layer is crucial to prevent oxygen desorption from the dielectric during annealing. Small amounts of oxidized gallium and metallic arsenic are located at the HfO2/InGaAs interface. The thickness of the HfO2 layer remains stable under the thermal treatments. Annealing affects the In 3d5/2 and Ga 3p signals. From the angular dependence of the peak intensities and the detailed knowledge of the structure of the films, it was possible to determine that annealing causes In and Ga out-diffusion into the metallic layer, and also to quantify the amount of transported matter. This, along with density functional theory calculations, allowed for an estimation of the activation energy of the diffusion of indium through HfO2.

Adsorption behavior of the ternary system of phospholipid 1-palmitoyl-2-oleoyl-sn-gylycero-3-phosphocholine in 3-hydroxypropionitrile with added tetrabutyl ammonium bromide

The adsorption behavior in a ternary system composed of the non-ionic surfactant POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and the ionic surfactant TBABr (tetrabutyl ammonium bromide) in the polar solvent HPN (3-hydroxypropionitrile) is investigated utilizing surface tension measurements and ARXPS (angular resolved X-ray photoelectron spectroscopy). The latter technique allows evaluating the surface excess of both surfactants. The combined experimental information (i.e. surface excess and surface tension) allows the determination of the chemical potential and thus the activities of both surfactants by virtue of the Gibbs equation. While the activity coefficient of TBABr is hardly affected by the presence of POPC, the activity coefficient of POPC strongly depends on both, the concentration of POPC and the concentration of TBABr. We observe the activity coefficient fPOPC to vary by more than 3 orders of magnitude in the 2-dimensional parameter space (cPOPC, cTBABr). This finding reflects and explains the surprising behavior of the surface tension: adding TBABr to the binary system POPC/HPN may increase or decrease the surface tension, depending on the POPC concentration. Inspection of these results suggests that mixed POPC/TBABr aggregates are formed at low POPC concentrations while the typical features of micelle formation are absent in this ternary system even at very low TBABr concentration.

Magnetic dichroism in angular resolved hard X-ray photoelectron spectroscopy from buried magnetic layers

This work reports on the measurement of magnetic dichroism in angular-resolved photoelectron spectroscopy from in-plane magnetized buried thin films. The high bulk sensitivity of hard X-ray photoelectron spectroscopy (HAXPES) in combination with circularly polarized radiation enables the investigation of the magnetic properties of buried layers. Angular distributions of high kinetic energy (7–8keV) photoelectrons in a range of about 60° were recorded in parallel to the energy distribution. Depending on purpose, energy and angular resolutions of 150–250meV and 0.17–2° can be accomplished simultaneously in such experiments. Experiments were performed on exchange-biased magnetic layers covered by thin oxide films. More specifically, the angular distribution of photoelectrons from the ferromagnetic layer Co2FeAl layer grown on MnIr exchange-biasing layer was investigated where the magnetic structure is buried beneath a MgO layer. Pronounced magnetic dichroism is found in the Co and Fe 2p states for all angles of emission. A slightly increased magnetic dichroism was observed for normal emission in agreement with theoretical considerations.

Surface Electronic Structure of [XMIm]Cl Probed by Surface‐Sensitive Spectroscopy

We apply electron spectroscopy methods with different surface sensitivities to elucidate the DOS of the surface and the near-surface region of [XMIm]Cl (X=octyl, hexyl, butyl, and ethyl alkyl chain) ionic liquids. Using metastable induced electron spectroscopy (MIES) we are able to detect the density of states in front of the outermost surface, whereas ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS) measurements provide lower surface sensitivity. The assignment of certain structures in the valence band spectra to particular atoms/functional groups of the ionic liquid based on DFT calculations and the reconstruction of PES spectra enables us to obtain information on the dominating groups at the surface, or in other words, on the molecular/ionic arrangement and orientation at the surface. From angular resolved XPS it is concluded that the alkyl chains dominate at the outermost surface. In agreement with this a decreasing chlorine signal is observed in the UPS spectra for ionic liquids with increasing alkyl chain length. The analysis of the MIES data shows that in case of [OMIm]Cl--in contrast to UPS and XPS--no Cl-induced features are visible in the MIES spectra at all and that the MIES spectra are dominated by the [OMIm](+) alkyl chain.

Full depth profile of passive films on 316L stainless steel based on high resolution HAXPES in combination with ARXPS

Depth profiles of the passive films on stainless steel were based on analysis with the non-destructive hard X-ray photoelectron spectroscopy (HAXPES) technique in combination with the angular resolved X-ray photoelectron spectroscopy (ARXPS). The analysis depth with ARXPS is within the passive film thickness, while the HAXPES technique uses higher excitation energies (between 2 and 12keV) also non-destructively probing the chemical content underneath the film. Depth profiles were done within and underneath the passive film of 316L polarized in acidic solution.The passive film thickness was estimated to 2.6nm for a sample that was polarized at 0.6V and the main component in the passive film is, as expected, chromium. From the high resolution HAXPES spectra we suggest chromium in three different oxidation states present. Also for iron three oxides were detected. Gradients of chromium and iron concentrations and oxidation states within the film and an enrichment of nickel within a 0.5nm layer directly underneath the passive film are some of the results discussed.

Magnetometry of buried layers—Linear magnetic dichroism and spin detection in angular resolved hard X-ray photoelectron spectroscopy

The electronic properties of buried magnetic nano-layers were studied using the linear magnetic dichroism in the angular distribution of photoemitted Fe, Co, and Mn 2p electrons from a CoFe–Ir78Mn22 multi-layered sample. The buried layers were probed using hard X-ray photoelectron spectroscopy, HAXPES, at the undulator beamline P09 of the 3rd generation storage ring PETRA III. The results demonstrate that this magnetometry technique can be used as a sensitive element specific probe for magnetic properties suitable for application to buried ferromagnetic and antiferromagnetic magnetic materials and multilayered spintronics devices. Using the same instrument, spin-resolved Fe 2p HAXPES spectra were obtained from the buried layer with good signal quality.