Mn 3s Research Articles

X-ray photoelectron spectroscopy and magnetism of Mn 1−xAl xNi alloys

X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), magnetization and magnetic susceptibility of Mn 1− x Al x Ni alloys are reported. A change in the crystallographic structure takes place around x=0.4 from CuAuI to CsCl (B2) structure type. For x0.5 a mixed B2+L2 1 state exists which incorporates antiferromagnetic (B2) and ferromagnetic (L2 1) parts. A direct evidence for the existence of local moments on Mn sites in Mn 1- x Al x Ni alloys is given by the exchange splitting of XPS Mn 3s and Mn 2p3/2 core levels. The gradual filling of the Ni 3d band as the Al concentration increases can be explained by the hybridization of the Ni 3d band and Al 3sp states.

Ferromagnetism and increased ionicity in epitaxially grownTbMnO3films

Thin films of TbMnO3 have been grown on SrTiO3 substrates. The films grow under compressive strain and are only partially clamped to the substrate. This produces remarkable changes in the magnetic properties and, unlike the bulk material, the films display ferromagnetic interactions below the ordering temperature of similar to 40 K. X-ray photoemission measurements in the films show that the Mn 3s splitting is 0.3 eV larger than that of the bulk. Ab initio embedded-cluster calculations yield Mn 3s splittings that are in agreement with the experiment and reveal that the larger observed values are due to a larger ionicity of the films.

Synthesis of monodisperse nanocrystals of manganese oxides

The nanocrystals Mn3O4 powder have been prepared using [Bis(salicylidiminato)manganese(II) ] as precursor. Effect of oleylamine and triphenylphosphine on particle morphology has been investigated. Transmission electron microscopy (TEM) analysis demonstrated nanocrystals Mn3O4 with an average diameter of about 20 nm. The structural study by X-ray diffraction (XRD) indicates that these nanocrystals have pure tetragonal phase. The phase pure samples were characterised using X-ray photoelectron spectroscopy (XPS) for both Mn 2p and Mn 3s levels. The values of binding energies are consistent with the relative values reported in the literature.

Adhesion and Cu Diffusion Barrier Properties of a MnOx Barrier Layer Formed with Thermal MOCVD

AbstractA thin-amorphous MnOx layer using self-forming barrier process with a Cu-Mn alloy shows good adhesion and diffusion barrier properties between copper and dielectric layer, resulting in excellent reliability for stress and electromigration. Meanwhile, chemical vapor deposition (CVD) can be employed for conformal deposition of the barrier layer in narrow trenches and vias for future technology node. In our previous research, a thin and uniform amorphous MnOx layer could be formed on TEOS-oxide by thermal metal-organic CVD (MOCVD), showing a good diffusion barrier property. In addition, a good adhesion strength is necessary between a Cu line and a dielectric layer not only to ensure good SM and EM resistance but also to prevent film delamination under mechanical or thermal stress conditions during fabrication process such as chemical mechanical polishing or high temperature annealing. To date, no information is available with regard to the adhesion property of CVD-MnOx. In this work, we report diffusion barrier property in further detail and adhesion property in PVD-Cu/CVD-MnOx/SiO2/Si. The temperature dependence of the adhesion property is correlated with the chemical composition and valence state of Mn investigated with SIMS and Raman spectroscopy.Substrates were p-type Si wafers having a plasma-TEOS oxide of 100nm in thickness. CVD was carried out in a deposition chamber. A manganese precursor was vaporized and introduced into the deposition chamber with H2 carrier gas. After the CVD, a Cu overlayer was deposited on some samples using a sputtering system in load lock chamber of the CVD machine. The diffusion barrier property of the MnOx film was investigated in annealed samples at 400 oC for 100 hours in a vacuum of better than 1.0×10-5 Pa. The Adhesion property of Mn oxide was investigated by Scotch tape test in the as-deposited and in the annealed Cu/CVD-MnOx/TEOS samples. The obtained samples were analyzed for thickness and microstructure with TEM, chemical bonding states of the MnOx layer with XPS, and composition of each layer with SIMS.In the CVD deposition below 300 °C, no Cu delamination was observed both in the as-deposited and in the annealed Cu/CVD-MnOx/SiO2 samples. On the other hand, in the CVD deposition at 400 °C, the Cu films were delaminated from the CVD-MnOx/TEOS substrates. The XPS peak position of Mn 2p and Mn 3s spectra indicated that the valence state of Mn in the as-deposited barrier layer below 400 °C was 2+. Composition analysis with SIMS as well as Raman also indicated the presence of a larger amount of carbon at 400 °C than at less than 300 °C. The good adhesion between Cu and MnO could be attributed to an amount of carbon inclusion in the CVD barrier layer.

Effects of substitution of Ni by Sb in MnNi

AbstractThe structural, electronic and magnetic structures of MnNi1–x Sbx alloys and compounds have been investigated by X‐ray diffraction, X‐ray photoelectron spectroscopy, magnetization and magnetic susceptibility measurements. The substitution of Ni by Sb leads to drastic changes both in the crystallographic and electronic structure, with remarkable modifications in the magnetic properties of the investigated systems. The most important feature of the XPS spectra is the well‐defined magnetic exchange splitting of the Mn 3s core levels of all investigated alloys, giving a direct evidence of the existence of local magnetic moments in the Anderson's sense confined on Mn sites. In order to investigate the hybridization between the Mn and Ni 3d states and the Sb 5p states, the XPS valence band spectra were calculated and compared to the experimental spectra. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Synthesis of Mn 3O 4 nanoparticles by thermal decomposition of a [bis(salicylidiminato)manganese(II)] complex

The present investigation reports on the novel synthesis of Mn 3O 4 nanoparticles using thermal decomposition and their physicochemical characterization. The Mn 3O 4 nanoparticle powder has been prepared using [bis(salicylidiminato)manganese(II)] as a precursor. The effect of oleyl amine and triphenylphosphine on the particle morphology has been investigated. Transmission electron microscopy (TEM) analysis demonstrated Mn 3O 4 nanoparticles with an average diameter of about 25 nm. The structural study by X-ray diffraction (XRD) indicates that these nanoparticles have a pure tetragonal phase. The phase pure samples were characterized using X-ray photoelectron spectroscopy (XPS) for both Mn 2p and Mn 3s levels. The values of binding energies are consistent with related values reported in the literature.

X‐ray photoelectron spectroscopy and magnetism of MnPd1–xSbx alloys

AbstractX‐ray photoelectron spectroscopy, magnetization and magnetic susceptibility of MnPd1–x Sbx are reported. The substitution of Pd by Sb leads to drastic changes both in the crystallographic and electronic structure, with remarkably modifications in the magnetic properties of the investigated systems. The most important feature of the XPS spectra is the well‐defined magnetic exchange splitting of the Mn 3s core levels of all investigated alloys, giving a direct evidence of the existence of local magnetic moments in the Anderson's sense confined on Mn sites. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Manganese silicide single crystal and films deposited on Si(1 1 1): A comparative spectroscopic study

A comparative experimental study is presented of the electronic properties of MnSi films grown on Si(1 1 1) and of MnSi single crystals, using X-ray absorption spectroscopy (XAS), and core level and valence band photoemission spectroscopy (PES). No significant differences in the electronic structure of the two systems can be found. Absorption measurements on the Mn 2p threshold show a mixed valence ground state, where the multiplet structure is washed out by the hybridisation of the Mn 3d states with the Si sp states. These results are also confirmed by photoemission (PE) spectra from the valence band and the Mn 3s, 3p and 2p core levels. Strong attention has been paid to the effect of contamination. The occurrence of multiplet effects in the absorption spectra indicates unambiguously the localisation of the Mn 3d electrons in Mn–O bonds, which strongly influences the electronic properties of these systems.

Nanosize Mn 3O 4 (Hausmannite) by microwave irradiation method

The present investigation reports, the novel synthesis of nanosize Mn 3O 4 powder with nanorods using microwaves and its physicochemical characterization. The nanosize Mn 3O 4 powder has been prepared using manganese nitrate as a precursor and effect of ethanolamine and ethylenediamine on particle morphology has been studied. The microwave irradiation has been carried out in the range 50–500 W and it was observed that formation of Mn 3O 4 takes place at 50 W. TEM analysis demonstrated nanosize Mn 3O 4 powder and nanorods with an average diameter of about 10 nm. The structural study by XRD indicates that these nano-powders have pure tetragonal phase. The phase pure samples were characterized using X-Ray Photoelectron Spectroscopy (XPS) for both Mn 2p and Mn 3s levels. The values of binding energies are consistent with the relative values reported in the literature. The metallic impurity levels have been characterized using Inductively Coupled Plasma-Optical Emission Spectrophotometer (ICP-OES).

Evidence forMn2+ions at surfaces ofLa0.7Sr0.3MnO3thin films

We present a detailed investigation of the valence of manganese sites at the surface of colossal magnetoresistance La0.7Sr 0.3MnO3 (LSMO) thin films by x-ray absorption spectroscopy (XAS). The XAS Mn L-edge spectra of epitaxial LSMO films usually show a peak or shoulder at 640 eV. Differences in the intensity of this feature are commonly attributed to slight changes in the Mn3+/Mn4+ ratio or the crystal field strength. By comparison of different XAS spectra of LSMO thin films with the known multiplet structure of Mn2+ in a cubic crystal field, we assign this 640-eV feature to Mn2+ ions. XAS with increased surface sensitivity, combined with photon energy-dependent photoelectron spectroscopy measurements of the Mn(3s) exchange splitting, show that the Mn2+ species are mainly located at the surface. The Mn2+ scenario indicates significant modification of the LSMO surface with respect to the bulk properties that should be taken into account in all the charge and spin tunneling and injection experiments. © 2005 The American Physical Society.

Valence state of Mn in charge-ordering Pr 0.5Ca 0.5MnO 3− δ studied by Mn 3s photoemission spectroscopy

Mn 3s photoemission spectroscopy has been performed at 300 and 100 K for Pr 0.5Ca 0.5MnO 3− δ which undergoes a charge-ordering transition around 235 K with decreasing temperature. We have observed in the Mn 3s spectrum the change in the Mn valency of Pr 0.5Ca 0.5MnO 3− δ accompanied by the transition. The Mn 3s spectrum at 300 K for Pr 0.5Ca 0.5MnO 3− δ is nearly identical to that of La 1.2Sr 1.8Mn 2O 7 in which the formal valence of the Mn ion is +3.4. This is consistent with the fact that the oxygen deficiency δ is 0.05 for the present sample. On the other hand the Mn 3s spectrum at 100 K is well reproduced by a superposition of those for LiMnO 2 with Mn 3+ and for SrMnO 3 with Mn 4+, while the mean Mn valency at 100 K remains being +3.4. This indicates that the Mn ions in Pr 0.5Ca 0.5MnO 3− δ are in the two different valence states below the transition temperature.

Spin-state effects on the outer core-level multiplet structures for high-spin Mn molecular clusters

Oxo-bridged manganese polynuclear complexes have applications in a variety of technologies, such as single-molecule nanomagnets, catalysis, and photosynthetic redox chemistry. X-ray photoemission spectroscopy was used to study the Mn 3p, 3s, and valence band electronic behavior as a function of Mn cluster structural properties, where the cluster size and nuclearity are systematically varied. Results show a chemical shift of the Mn 3p3/2,1/2 spin–orbit pair related to the cluster size and nuclearity. In addition, the Mn 3s S7 and S5 final state multiplet components shift since they involve the binding energy of a ligand valence electron. In addition, the branching ratio of the S7:S5 states is related to the 3s–3d electron correlation. Specifically, in the S7 state, the remaining 3s electron is well correlated with 3d electrons of parallel spin, while in the S5 state, the two spins are antiparallel. Changes in this electron correlation are clearly observed in the S7:S5 branching ratio as a function of cluster size and ligand electronegativity.

Importance of interatomic hole screening in core-level spectroscopy of transition metal oxides: Mn3shole states in MnO

Ab initio theoretical results are reported to determine the role of interatomic screening of the metal core hole in Mn 3s x-ray photoelectron spectra (XPS) of MnO. We present information that finally resolves the controversy about the relative importance of intra-atomic and interatomic effects to the XPS spectra of ionic manganese compounds. We focus on the transitions to high-spin 3s core hole states, using a nonorthogonal configuration interaction method. This method allows for a balanced treatment of configurations that involve different degrees of screening of the core hole. The differences between MnO and NiO are analyzed. Although at first glance the two XPS spectra seem to have similar features, the 3s hole final states have completely different characteristics. In MnO, interatomic screening of the core hole is found to play a minor role. This is in contrast with NiO, where the inclusion of interatomic screening of the metal core hole has been shown to be crucial for a proper explanation of the Ni 3s XPS. The main reason for the difference is an essentially atomic effect, namely the smaller electron affinity of Mn as compared to Ni. We have assigned the weak feature observed in the Mn 3s XPS spectrum of MnO at around 10 eV to be a charge-transfer-type high spin satellite.

Manganese Dioxide (MnO2) by XPS

XPS spectra of manganese dioxide (MnO2) powder are presented. The spectra were collected using monochromated Al Kα x-rays. Spectra include survey scan, the Mn 2p, 3p, and 3s regions, the O 1s region, and the Mn LMM Auger transitions.

Lithium Manganese Oxide (LiMn2O4) by XPS

XPS spectra of lithium manganese oxide (LiMn2O4) are presented. The spectra were collected using monochomated Al Kα x-rays. Spectra include survey scan, the Li 1s region, the Mn 2p, 3p, and 3s regions, the O 1s region, and the Mn LMM Auger transitions.

Preparation of Manganese Oxide Thin Films by Electrolysis/Chemical Deposition and Electrochromism

Manganese oxide thin films were deposited onto transparent and conductive tin oxide-coated glass substrates by electrochemical deposition (at 1.2 V vs. Ag/AgCl) and subsequent chemical [electrolysis/chemical (EL/C)] processing in a manganese ammine complex solution at pH 8. Characterization by X-ray diffraction (XRD) of the films revealed that the crystal structure formed in the films by EL/C deposition is assigned to and/or X-ray photoelectron spectroscopy (XPS) was also performed to focus on exchange splitting effect shown in Mn 3s spectra and peak analyses of O 1s spectra of the films. From electrochemical, quartz crystal microbalance, XRD, XPS, and atomic force microscope studies, a mechanism of film growth was illustrated, featuring time course of rest potential during chemical process. The XPS data also suggested that the electrochromic behavior, turning brown and light yellow by the anodic and cathodic polarization in potassium borate buffer solution at pH 10, originates from a transformation between two oxygen groups in hydroxide (Mn-O-H) and oxide (Mn-O-Mn) accompanied by the change in valence of Mn. The repeated EC switching performance of the films was also assayed. © 2001 The Electrochemical Society. All rights reserved.

High Spin Mn Molecular Clusters: Spin State Effects On the Outer Core-Level Multiplet Structures

AbstractOxo-bridged manganese polynuclear complexes have applications in a variety of technologies, such as single-molecule nanomagnets, catalysis and photosynthetic redox chemistry. The reason that these types of compounds are capable of such important and varied technologies is thought to be because they possess ground states with large spin values. However, the electronic, structural and magnetochemical relationships are not well understood and need to be thoroughly investigated to adequately explain why Mn is such an integral part of so many useful processes. X-ray photoemission spectroscopy was used to study the Mn 3p, 3s and valence band electronic behavior as a function of Mn cluster structural properties, where the cluster size and nuclearity are systematically varied. Results show a chemical shift of the Mn 3p3/2,1/2 spin-orbit pair related to the cluster size and nuclearity. Also, the Mn 3s 7S and 5S final state multiplet components shift since they involve the binding energy of a ligand valence electron. In addition, the branching ratio of the 7S:5S states is related to the 3s–3d electron correlation. Specifically, in the 7S state, the remaining 3s electron is well correlated with 3d electrons of parallel spin, while in the 5S state the two spins are antiparallel. Changes in this electron correlation are clearly observed in the 7S:5S branching ratio as a function of cluster size and ligand electronegativity.

Core-level satellites and outer core-level multiplet splitting in Mn model compounds

We report a systematic study of the Mn 2p, 3s, and 3p core-level photoemission and satellite structures for Mn model compounds. Charge transfer from the ligand state to the 3d metal state is observed and is distinguished by prominent shake-up satellites. We also observe that the Mn 3s multiplet splitting becomes smaller as the Mn oxidation state increases, and that 3s–3d electron correlation reduces the branching ratio of the S:7S5 states in the Mn 3s spectra. In addition, as the ligand electronegativity decreases, the spin-state purity is lost in the 3s spectra, as evidenced by peak broadening. Our results are best understood in terms of the configuration–interaction model including intrashell electron correlation, charge transfer, and final-state screening.

Manganese Oxide Thin Film Preparation by Potentiostatic Electrolyses and Electrochromism

Manganese oxide thin films were deposited on transparent conducting tin oxide glass substrates by potentiostatic anodic electrolysis of alkaline solution of a manganese ammine complex at 298 K. The effects of varying deposition potentials on the microstructure and the electrochromic (EC) properties of the films were investigated. Characterization of films by X‐ray diffraction revealed that two distinct potential regions (lower and higher than 0.3 V vs. Ag/AgCl) were available for the film deposition; the crystal structure of the film deposited at lower and higher regions were and/or and , respectively. X‐ray photoelectron spectroscopy (XPS) analyses of the films featuring exchange splitting effect on Mn 3s spectra indicated that the valence of manganese in the films prepared at lower and higher potential regions are mixtures of divalence‐trivalence and of trivalence‐tetravalence, respectively. The XPS analysis also revealed that terminal chemical bonding species of the films are a mixture of hydroxide (Mn‐O‐H) and oxide (Mn‐O‐Mn). The mechanism of the EC process, by which the color change between brown and light yellow occurs, could be explained in terms of the transformation between these two oxygen groups in Mn‐O‐H and Mn‐O‐Mn, accompanied by the change in valence of Mn. The EC durability of the films in switching performance was also assessed. © 2000 The Electrochemical Society. All rights reserved.

Exchange splitting of the Cr, Fe and Mn 3s XPS spectra in some ternary magnetic semiconductor sulphides

X-ray photoelectron spectroscopy (XPS) was used to analyse the exchange splitting of the 3s core levels of the 3d transition metals in the magnetic semiconductor single crystals CdCr2S4, MnCr2S4, FeCr2S4, Fe0.5Cu0.5Cr2S4 and polycrystal ZnCr2S4. A well defined splitting of the Cr, Fe and Mn 3s core levels has been found. No splitting of the Cu 3s line was observed. The values of the local magnetic moments and the valence configurations of the ions are discussed. The Cr ions are shown to be in a 3d3 state in all the studied compounds. The Fe ions are considered to be in a 3d6 state in the FeCr2S4 compound. In the MnCr2S4 a reduced value of the splitting for Mn2+ was observed. The Cu ions are in a diamagnetic 3d10 configuration in the Fe0.5Cu0.5Cr2S4 crystal.