X-ray Magnetic Circular Dichroism Research Articles

Anomalous Ferromagnetism of quasiparticle doped holes in cuprate heterostructures revealed using resonant soft X-ray magnetic scattering

We report strong ferromagnetism of quasiparticle doped holes both within the ab-plane and along the c-axis of Cu-O planes in low-dimensional Au/d-La1.8Ba0.2CuO4/LaAlO3(001) heterostructures (d = 4, 8 and 12 unit-cells) using resonant soft X-ray and magnetic scattering together with X-ray magnetic circular dichroism. Interestingly, ferromagnetism is stronger at a hole doped peak and at an upper Hubbard band of O with spin-polarization degree as high as 40%, revealing strong ferromagnetism of Mottness. For in-ab-plane spin-polarizations, the spin of doped holes in O2p–Cu3d–O2p is a triplet state yielding strong ferromagnetism. For out-of-ab-plane spin-polarization, while the spins of doped holes in both O2p–O2p and Cu3d–Cu3d are triplet states, the spin of doped holes in Cu3d–O2p is a singlet state yielding ferrimagnetism. A ferromagnetic-(002) Bragg-peak of the doped holes is observed and enhanced as a function of d revealing strong ferromagnetism coupling between Cu-O layers along the c-axis.

Enhanced d−p hybridization intertwined with anomalous ground state formation in the van der Waals itinerant magnet Fe5GeTe2

${\mathrm{Fe}}_{5}{\mathrm{GeTe}}_{2}$ is a van der Waals (vdW)-coupled unconventional ferromagnetic metal with a high Curie temperature (${T}_{\mathrm{C}}$) exceeding 300 K. The formation of an anomalous ground state significantly below ${T}_{\mathrm{C}}$ has received considerable attention, resulting in increased interest in understanding the spin-polarized electronic state evolution near the Fermi energy (${E}_{\mathrm{F}}$) as a function of temperature. Despite recent extensive studies, a microscopic understanding of the spin-polarized electronic structure around ${E}_{\mathrm{F}}$ has not yet been established owing to the intrinsic complexity of both the crystal and band structures. In this study, we investigate the temperature dependence of element-specific soft x-ray magnetic circular dichroism (XMCD). A systematic temperature evolution in the XMCD signal from both magnetic Fe and its ligand Te is clearly observed. More importantly, the enhancement in the hybridization between the Fe $3d$ and Te $5p$ states at low temperature in the zero-magnetic field limit is revealed. We discuss the implications of our observation in line with possible emergence of an exotic magnetic ground state in ${\mathrm{Fe}}_{5}{\mathrm{GeTe}}_{2}$.

Structural, Optical, and Magnetic Properties of Erbium-Substituted Yttrium Iron Garnets.

We synthesized a series of slightly erbium-substituted yttrium iron garnets (Er:YIG), Y3–xErxFe5O12 at different Er concentrations (x = 0, 0.01, 0.05, 0.10, and 0.20) using a solid-state reaction and investigated their structural, magnetic, and optical properties as a function of Er concentration. The volume of the unit cell slightly increased with Er concentration and Er atoms predominately replaced Y atoms in the dodecahedrons of YIG. The optical properties exhibited certain decreases in reflectance in the 1500–1600 nm wavelength range due to the presence of Er3+. Despite the many unpaired 4f electrons in Er3+, the total magnetic moments of Er:YIG showed similar trends with temperatures and magnetic fields above 30 K. An X-ray magnetic circular dichroism study confirmed the robust Fe 3d magnetic moments. However, the magnetic moments suddenly decreased to below 30 K with Er substitution, and the residual magnetism (MR) and coercive field (HC) in the magnetic hysteresis loops decreased to below 30 K with Er substitution. This implies that Er substitution in YIG has a negligible effect on magnetic properties over a wide temperature range except below 30 K where the Er 4f spins are coupled antiparallel to the majority Fe 3d spins. Our studies demonstrated that above 30 K the magnetic properties of YIG are retained even with Er substitution, which is evidence that the Er doping scheme is applicable for YIG-based magneto-optical devices in the mid-infrared regime.

Magnetic phase diagram of iron at high pressure and temperature

Crystallographic structure and long-range magnetic order of iron have been measured in pressure-temperature domains of 2--18 GPa and 300--800 K, using x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD) in resistively heated diamond anvil cells under hydrostatic pressurizing conditions. A fine coverage of pressure-temperature space allowed monitoring $\ensuremath{\alpha}\ensuremath{\leftrightarrow}\ensuremath{\epsilon}, \ensuremath{\alpha}\ensuremath{\rightarrow}\ensuremath{\gamma}$, and $\ensuremath{\gamma}\ensuremath{\rightarrow}\ensuremath{\epsilon}$ transformations, evidencing large metastability phenomena. $\ensuremath{\alpha}$-Fe remains ferromagnetic under high pressure and temperature in its whole stability domain, and no magnetic response could be measured with XMCD in pure $\ensuremath{\gamma}$-Fe and $\ensuremath{\epsilon}$-Fe. Structural and magnetic transformations are observed concomitantly within experimental uncertainties.

Spin canting of Ni/CoO/Fe films grown on curved MgO(0 0 1) substrate

Using element-resolved x-ray magnetic circular dichroism (XMCD) and x-ray magnetic linear dichroism (XMLD) measurements, we determined the spin orientations of Ni, CoO and Fe films in Ni/CoO/Fe films grown on a curved MgO(001) substrate. We find that the vicinal surface of MgO(001) substrate results in a spin canting towards out-of-plane direction in the Ni and CoO films as a result of the interfacial coupling. The Ni spin canting angle increases monotonically with the vicinal angle in the studied range of 0–17° and the CoO spin canting angle increases more rapidly towards saturation only at a few degrees of the vicinal angle. The uniaxial magnetic anisotropy induced in the Ni layer by the Ni/CoO interfacial coupling is quantitatively determined and is shown to increase monotonically with the vicinal angle. Our result provides a new pathway for tailoring the spin orientation by modifying the substrate surface symmetry in combining with the ferromagnetic/antiferromagnetic interfacial interaction in thin-film based spintronic devices.

X-ray spectroscopy for the magnetic study of the van der Waals ferromagnet CrSiTe3 in the few- and monolayer limit

The study of magnetic order in few- and monolayer van der Waals materials poses a challenge to the most commonly employed magnetic characterization techniques as they normally lack magnetic sensitivity and/or lateral resolution enabling their thickness-dependent probing. Here we demonstrate the usefulness of x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements, carried out at the Cr and Te M 5 edges, for the study of the ferromagnetic semiconductor CrSiTe3 (CST) in the form of single- and few-layer flakes. By scanning the sample under the incident x-ray beam, a map of the exfoliated system was obtained, which reproduced the optical micrographs showing the detailed distribution and thicknesses of the flakes. In this way, XAS/XMCD was performed at selected sample areas, revealing the thickness-resolved spectroscopic and magnetic properties of the flakes, such as the spin and orbital magnetic moments. The spin moment, in line with the saturation field, is decreasing with film thickness, revealing a single-domain and out-of-plane magnetization for the thinnest films. For CST, the electronic properties are governed by the strong covalent bond between the Cr 3d(e g ) and Te 5p states, giving rise to a superexchange scenario. We observed a gradually increasing ratio of orbital to spin moment for thinner flakes, which could be due to a further increase of the covalent mixing. Hysteresis loops were recorded at the Cr L 3 edge, showing an open loop for 10 down to ∼3 layers, while the bulk shows a wasp-waist shaped loop. With the transition temperature from the soft to the hard ferromagnetic state decreasing with thickness, the monolayer shows a narrowed, closed loop at 10 K, suggesting its transition temperature 10 K. Our study demonstrates the unique capabilities of XAS/XMCD for the study of few-layer van der Waals magnets, highlighting the interplay between electron correlation and ferromagnetism in CST.

(Invited, Digital Presentation) Single-Atom Quantum Magnetism in 2D Materials

With the advent of 2D materials, the playground to study spins in dilute and non-dilute phases has expanded. This is appealing for utilizing the additional degrees of freedom of electron systems such as spin and valley and, from the fundamental point of view, to better understand atomic scale magnetic phenomena in low dimensional materials. Dilute magnetism in 2D materials can lead to complex magnetic phenomena (e.g., Kondo effect, RKKY-interactions, quantum relaxation and coherence), with potential for applications in spintronics (e.g., spin FETs) and quantum technologies (e.g., single-atom quantum memories). We are investigating how to selectively incorporate substitutional magnetic atoms (3d transition metals and 4f rare earths) in 2D materials, using ultra low energy ion implantation, and we characterize their structural, electronic, and magnetic properties [1]. Ultra-low energy (ULE) ion implantation allows us to precisely tune the kinetic energy of the ions, providing control over the form of incorporation and concentration while preserving the structural and electronic properties of graphene. Our approach is based on a wide range of characterization techniques (structural and electronic), including scanning tunneling microscopy and spectroscopy (STM/STS), Raman spectroscopy, synchrotron-based X-ray photoelectron spectroscopy (XPS), angle-resolved photoemission spectroscopy (ARPES), X-ray magnetic circular dichroism (XMCD), among others. These experimental studies are complemented by density functional theory (DFT) and molecular dynamics (MD) simulations. The new insights provided by our work establish a framework for the controlled incorporation of magnetic dopants in 2D materials, using ULE ion implantation.[1] P. C. Lin et al., ACS Nano 15(3), 5449-5458 (2021).

Magnetic molecules as local sensors of topological hysteresis of superconductors

Superconductors and magnetic materials, including molecules, are key ingredients for quantum computing and spintronics. However, only a little is known about how these materials interact in multilayer nanostructures like the hybrid architectures nowadays under development for such advanced applications. Here, we show that a single layer of magnetic molecules, Terbium(III) bis-phthalocyaninato (TbPc2) complexes, deposited under controlled UHV conditions on a superconducting Pb(111) surface is sensitive to the topology of the intermediate state of the superconductor, namely to the presence and evolution of superconducting and normal domains due to screening and penetration of an external magnetic field. The topological hysteresis of the superconducting substrate imprints a local evolution of the magnetisation of the TbPc2 molecules in the monolayer. Element and surface selective detection is achieved by recording the X-ray magnetic circular dichroism of the Tb atoms. This study reveals the impressive potential of magnetic molecules for sensing local magnetic field variations in molecular/superconductor hybrid devices, including spin resonators or spin injecting and spin filtering components for spintronics applications.

Slow Magnetic Relaxation of Dy Adatoms with In-Plane Magnetic Anisotropy on a Two-Dimensional Electron Gas.

We report on the magnetic properties of Dy atoms adsorbed on the (001) surface of SrTiO3. X-ray magnetic circular dichroism reveals slow relaxation of the Dy magnetization on a time scale of about 800 s at 2.5 K, unusually associated with an easy-plane magnetic anisotropy. We attribute these properties to Dy atoms occupying hollow adsorption sites on the TiO2-terminated surface. Conversely, Ho atoms adsorbed on the same surface show paramagnetic behavior down to 2.5 K. With the help of atomic multiplet simulations and first-principles calculations, we establish that Dy populates also the top-O and bridge sites on the coexisting SrO-terminated surface. A simple magnetization relaxation model predicts these two sites to have an even longer magnetization lifetime than the hollow site. Moreover, the adsorption of Dy on the insulating SrTiO3 crystal leads, regardless of the surface termination, to the formation of a spin-polarized two-dimensional electron gas of Ti 3dxy character, together with an antiferromagnetic Dy–Ti coupling. Our findings support the feasibility of tuning the magnetic properties of the rare-earth atoms by acting on the substrate electronic gas with electric fields.

Synchrotron X-ray spectroscopic study of the antiferromagnetic-ferromagnetic transition in Ni-doped FeRh epitaxial thin films

We investigate the change of magnetism and electronic structure across the antiferromagnetic (AFM) -ferromagnetic (FM) transition of Ni-doped FeRh epitaxial thin films by x-ray magnetic circular dichroism (XMCD) and hard x-ray photoemission spectroscopy (HAXPES). The Rh L edge XMCD results indicate that the remnant FM phase at low temperature possesses smaller Rh moment than the normal FM phase which can undergo AFM-FM transition. The HAXPES results confirm an increase of Rh 4d density of state at the Fermi level and a possible “well-screened” state at the Ni 2p photoemission in the FM phase. FM fluctuation of the inter-site Fe-Fe exchange coupling within the AFM phase can be interpreted from the temperature dependence of the Fe 2p HAXPES results.

Origin of the Unusual Ground-State Spin S = 9 in a Cr10 Single-Molecule Magnet.

The molecular wheel [Cr10(OMe)20(O2CCMe3)10], abbreviated {Cr10}, with an unusual intermediate total spin S = 9 and non-negligible cluster anisotropy, D/kB = -0.045(2) K, is a rare case among wheels based on an even number of 3d-metals, which usually present an antiferromagnetic (AF) ground state (S = 0). Herein, we unveil the origin of such a behavior. Angular magnetometry measurements performed on a single crystal confirmed the axial anisotropic behavior of {Cr10}. For powder samples, the temperature dependence of the susceptibility plotted as χT(T) showed an overall ferromagnetic (FM) behavior down to 1.8 K, whereas the magnetization curve M(H) did not saturate at the expected 30 μB/fu for 10 FM coupled 3/2 spin Cr3+ ions, but to a much lower value, corresponding to S = 9. In addition, the X-ray magnetic circular dichroism (XMCD) measured at high magnetic field (170 kOe) and 7.5 K showed the polarization of the cluster moment up to 23 μB/fu. The magnetic results can be rationalized within a model, including the cluster anisotropy, in which the {Cr10} wheel is formed by two semiwheels, each with four Cr3+ spins FM coupled (JFM/kB = 2.0 K), separated by two Cr3+ ions AF coupled asymmetrically (J23/kB = J78/kB = -2.0 K; J34/kB = J89/kB = -0.25 K). Inelastic neutron scattering and heat capacity allowed us to confirm this model leading to the S = 9 ground state and first excited S = 8. Single-molecule magnet behavior with an activation energy of U/kB = 4.0(5) K in the absence of applied field was observed through ac susceptibility measurements down to 0.1 K. The intriguing magnetic behavior of {Cr10} arises from the detailed asymmetry in the molecule interactions produced by small-angle distortions in the angles of the Cr-O-Cr alkoxy bridges coupling the Cr3+ ions, as demonstrated by ab initio and density functional theory calculations, while the cluster anisotropy can be correlated to the single-ion anisotropies calculated for each Cr3+ ion in the wheel.

Magnetic domain wall pinning in cobalt ferrite microstructures

A detailed correlative structural, magnetic and chemical analysis of (non-stoichiometric) cobalt ferrite micrometric crystals was performed by x-ray magnetic circular dichroism combined with photoemission microscopy, low-energy electron microscopy and atomic force microscopy. The magnetization vector inside the islands was resolved at the nanoscale, as obtained from magnetic images taken at different x-ray incidence angles. The location of the magnetic domain walls was correlated with the presence of different types of defects as revealed by the different microscopies. This, together with the results of micromagnetic simulations, suggests that the main source of pinning in these microcrystals are linear structural defects induced in the spinel structure by the substrate steps underneath the islands. Our result is of relevance for understanding the different magnetic properties of thin films and nanostructures as compared with the corresponding bulk materials.

Cr doping-induced ferromagnetism in the spin-glass Cd1−xMnxTe studied by x-ray magnetic circular dichroism

The prototypical diluted magnetic semiconductor Cd1−xMnxTe is a spin glass (x < 0.6) or an antiferromagnet (x > 0.6) but becomes ferromagnetic upon doping with a small amount of Cr atoms. To investigate the origin of the ferromagnetism in Cd1−x−yMnxCryTe, we have studied its element specific magnetic properties by x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD). Measured XAS and XMCD spectra indicate that both Cr and Mn atoms are divalent and that the magnetic moments of Cr and Mn are aligned parallel. The magnetization of Mn increases with increasing Cr content, suggesting that ferromagnetic interaction exists between neighboring Mn and Cr ions despite the largely antiferromagnetic interaction between Mn atoms. By analyzing the element-specific magnetization curves, we conclude that Cr doping leads to the formation of ferromagnetic or superparamagnetic clusters consisting of several Cr ions surrounded by a much larger number of Mn ions.

Photon correlation spectroscopy with heterodyne mixing based on soft x-ray magnetic circular dichroism

Many magnetic equilibrium states and phase transitions are characterized by fluctuations. Such magnetic fluctuation can in principle be detected with scattering-based x-ray photon correlation spectroscopy (XPCS). However, in the established approach of XPCS, the magnetic scattering signal is quadratic in the magnetic scattering cross section, which results not only in often prohibitively small signals but also in a fundamental inability to detect negative correlations (anticorrelations). Here, we propose to exploit the possibility of heterodyne mixing of the magnetic signal with static charge scattering to reconstruct the first-order (linear) magnetic correlation function. We show that the first-order magnetic scattering signal reconstructed from heterodyne scattering now directly represents the underlying magnetization texture. Moreover, we suggest a practical implementation based on an absorption mask rigidly connected to the sample, which not only produces a static charge scattering signal but also eliminates the problem of drift-induced artificial decay of the correlation functions. Our method thereby significantly broadens the range of scientific questions accessible by magnetic x-ray photon correlation spectroscopy.

Structural, magnetic and Magneto-transport properties of Mn-doped SiGe thin films

Mn-doped polycrystalline SiGe thin films are fabricated by radio frequency magnetron sputtering and subsequent rapid thermal annealing. Structural characterizations show that the Mn atoms are distributed uniformly in the SiGe matrix and mainly occupy the substitutional sites with 2+ state. X-ray magnetic circular dichroism signals reveal the spin and orbital magnetic moment information of the samples. Magnetic measurements show that the Curie temperature is up to ∼ 290 K and the effective magnetic moment is about 1.57 μB/Mn. Magneto-transport measurements reveal anomalous Hall effect, another signal of ferromagnetism in the samples. Our results provide insights into the structure and the ferromagnetism of the Mn-doped SiGe thin films and may be useful for related spintronic applications.

Interfacial magnetic vortex formation in exchange-coupled hard-soft magnetic bilayers

The exchange coupling between a hard magnetic layer MnBi and a soft magnetic layer Co-Fe has been found to significantly improve the maximum energy product. In this work, the spin structure of exchange-coupled MnBi:Co-Fe bilayers is experimentally investigated by X-ray magnetic circular dichroism (XMCD) and polarized neutron reflectometry (PNR). We find that the out-of-plane magnetization reversal process of the MnBi:Co-Fe bilayer structure involves formation of a curling-type twisting of the magnetization in the film plane at low or intermediate reversal fields. Micromagnetic simulations are further performed to provide a detailed view of the spins at the curling center. Reminiscent of chiral spin structures known as spin bobbers, this curling in the exchange-coupled hard-soft magnetic bilayers is a new type of skyrmionic spin structure and worth further investigation.

Magnetic Properties and Electronic Configurations of Mn Ions in the Diluted Magnetic Semiconductor Ba1−xKx(Zn1−yMny)2As2 Studied by X-ray Magnetic Circular Dichroism and Resonant Inelastic X-ray Scattering

The magnetic properties and the electronic excitations of the new diluted magnetic semiconductor Ba$_{1-x}$K$_{x}$(Zn$_{1-y}$Mn$_{y}$)$_{2}$As$_{2}$ have been studied by x-ray magnetic circular dichroism (XMCD) and resonant inelastic x-ray scattering (RIXS) at the Mn $L_{2,3}$ edge. The sum rule analysis of the XMCD spectra yields the net spin moment of $0.45\mu_{\text{B}}$/Mn and the small orbital moment of $0.05\mu_{\text{B}}$/Mn. This indicates that the Mn atoms are in the high-spin configurations of $d^{5}$, whereas the presence of competing ferromagnetic and antiferromagnetic interactions between the Mn ions reduces the net spin moment. RIXS spectra show broad peaks from 1 to 6 eV energy loss, which originate from the $d$-$d$ crystal field excitations of the Mn ions. Based on a comparison of the RIXS line shapes with those of Ga$_{1-x}$Mn$_{x}$As, we conclude that the ground state of Mn in Ba$_{1-x}$K$_{x}$(Zn$_{1-y}$Mn$_{y}$)$_{2}$As$_{2}$ consists not only of the charge-transferred $3d^{5}\underline{L}$ electron configuration ($\underline{L}$: ligand hole) with weakly bound holes as in Ga$_{1-x}$Mn$_{x}$As, but also of the pure $3d^{5}$ configuration with free holes.

As-Se Pentagonal Linkers to Induce Chirality and Polarity in Mixed-Valent Fe-Se Tetrahedral Chains Resulting in Hidden Magnetic Ordering.

A novel mixed-valent hybrid chiral and polar compound, Fe7As3Se12(en)6(H2O), has been synthesized by a single-step solvothermal method. The crystal structure consists of 1D [Fe5Se9] chains connected via [As3Se2]-Se pentagonal linkers and charge-balancing interstitial [Fe(en)3]2+ complexes (en = ethylenediamine). Neutron powder diffraction verified that interstitial water molecules participate in the crystal packing. Magnetic polarizability of the produced compound was confirmed by X-ray magnetic circular dichroism (XMCD) spectroscopy. X-ray absorption spectroscopy (XAS) and 57Fe Mössbauer spectroscopy showed the presence of mixed-valent Fe2+/Fe3+ in the Fe-Se chains. Magnetic susceptibility measurements reveal strong antiferromagnetic nearest neighbor interactions within the chains with no apparent magnetic ordering down to 2 K. Hidden short-range magnetic ordering below 70 K was found by 57Fe Mössbauer spectroscopy, showing that a fraction of the Fe3+/Fe2+ in the chains are magnetically ordered. Nevertheless, complete magnetic ordering is not achieved even at 6 K. Analysis of XAS spectra demonstrates that the fraction of Fe3+ in the chain increases with decreasing temperature. Computational analysis points out several competing ferrimagnetic ordered models within a single chain. This competition, together with variation in the Fe oxidation state and additional weak intrachain interactions, is hypothesized to prevent long-range magnetic ordering.

Resonant inelastic x-ray scattering in Ca3LiOsO6 from first-principles

We have investigated the electronic and magnetic properties of the transition metal oxide (TMO) Ca3LiOsO6 within the density functional theory (DFT) using the generalized gradient approximation while taking into account strong Coulomb correlations (GGA+U) in the framework of the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. Ca3LiOsO6 is an insulator and forms the K4CdCl6-type crystal structure with relatively high Néel temperature TN = 117 K. Despite of the large strength of spin–orbit coupling, it has only a small effect on the electronic and magnetic properties of Ca3LiOsO6. We have also investigated theoretically the x-ray absorption spectra (XAS), x-ray magnetic circular dichroism (XMCD) and resonant inelastic x-ray scattering (RIXS) spectra at the Os L3 edge. The experimentally measured RIXS spectrum of Ca3LiOsO6 in addition to the elastic scattering peak at 0 eV possesses a sharp feature below 2 eV corresponding to transitions within the Os t2g levels. The excitation located at 4.5 eV is due to t2g→eg transitions. The third wide structure situated at 6–8 eV appears due to ligand-to-metal charge transfer excitations: d−d transitions to the Os t2g manifold from the Os 5dO states derived from the ”tails” of oxygen 2p states. The high energy structure at 10–11.5 eV is due to Os 5dO→eg interband transitions. At higher energy above 11 eV transitions from the Os 5dO states to the empty Ca 5d states are located. We have investigated the effect of SO coupling, Coulomb correlations and core-hole effect on the energy band structure, XAS, XMCD, and RIXS spectra in Ca3LiOsO6.

Development of magnetism in Fe-doped magnetic semiconductors: Resonant photoemission and x-ray magnetic circular dichroism studies of (Ga,Fe)As

Fe-doped III-V ferromagnetic semiconductors (FMSs) such as (In,Fe)As, (Ga,Fe)Sb, (In,Fe)Sb, and (Al,Fe)Sb are promising materials for spintronic device applications because of the availability of both $\mathrm{n}$- and $\mathrm{p}$-type materials and the high Curie temperatures. On the other hand, (Ga,Fe)As, which has the same zinc-blende crystal structure as the Fe-doped III-V FMSs, shows paramagnetism. The origin of the different magnetic properties in the Fe-doped III-V semiconductors remains to be elucidated. To address this issue, we use resonant photoemission spectroscopy (RPES) and x-ray magnetic circular dichroism (XMCD) to investigate the electronic and magnetic properties of the Fe ions in a paramagnetic $({\mathrm{Ga}}_{0.95},{\mathrm{Fe}}_{0.05})\mathrm{As}$ thin film. The observed Fe $2p\text{\ensuremath{-}}3d$ RPES spectra show that the Fe $3d$ states are similar to those of ferromagnetic (Ga,Fe)Sb. The estimated Fermi level is located in the middle of the band gap in (Ga,Fe)As. The Fe ${L}_{2,3}$ XMCD spectra of $({\mathrm{Ga}}_{0.95},{\mathrm{Fe}}_{0.05})\mathrm{As}$ show preedge structures, which are not observed in the Fe-doped FMSs, indicating that the minority-spin (\ensuremath{\downarrow}) ${e}_{\ensuremath{\downarrow}}$ states are vacant in $({\mathrm{Ga}}_{0.95},{\mathrm{Fe}}_{0.05})\mathrm{As}$. The XMCD results suggest that the carrier-induced ferromagnetic interaction in $({\mathrm{Ga}}_{0.95},{\mathrm{Fe}}_{0.05})\mathrm{As}$ is short ranged and weaker than that in the Fe-doped FMSs. The experimental findings suggest that the electron occupancy of the ${e}_{\ensuremath{\downarrow}}$ states contributes to the appearance of ferromagnetism in the Fe-doped III-V semiconductors, for $\mathrm{p}$-type as well as $\mathrm{n}$-type compounds.