Cr Magnetic Moments Research Articles

Improving the Curie temperature of monolayer CrBr3 by Li adsorption: A first-principles study

The monolayer CrBr3, as an intrinsic magnetic semiconductor, holds great promise for future electronic and spintronic devices. However, the lower Curie temperature (TC) limits the applications. In this study, we investigated the impact of Li adsorption on the stability, electronic and magnetic properties of monolayer CrBr3 by performing first-principles calculations. Our results reveal that Li adsorption can lead to a semiconductor-to-half-metal transition, the spin-down band gap exhibits a linear variation in response to the adsorption coverage. Furthermore, Li adsorption can further enhance the Cr magnetic moment, and make the TC twice as large as that of pristine CrBr3. Significantly, the increase in TC derives from the competition between the stronger ferromagnetic superexchange among Cr-Br-Cr and the weaker direct antiferromagnetic exchange among Cr-Cr. Our results not only offer a simple and feasible approach to modulate the electronic structure and magnetism of monolayer CrBr3, but also may open up new prospects for utilizing monolayer CrBr3 in next-generation nanoelectronic and spintronic devices.

Origin of perpendicular magnetic anisotropy in Fe0.6Al0.4/Cr0.8Al0.2 metallic superlattice

Abstract In this study, we investigated a perpendicular magnetic anisotropy (PMA) in a ferromagnet/antiferromagnetic stacking structure without using heavy metal elements. The Fe0.6Al0.4/Cr0.8Al0.2/Fe0.6Al0.4 stacked films exhibited perpendicular magnetization. We discussed the origin of the PMA based on the Cr0.8Al0.2 thickness, t Cr-Al (= 0.6 – 3.0 nm) dependences of the uniaxial anisotropy energy density K u, elastic strain ε 1 – ε 3, and unit cell volume V of the Fe0.6Al0.4 and Cr0.8Al0.2 layers. The K u value was approximately 25 kJ/m3, independent of t Cr-Al. The positive ε 1 – ε 3, i.e., the tensile strain in the Cr0.8Al0.2 layer can promote the PMA. The possible degradation of PMA due to the lattice relaxation with increasing t Cr-Al could be compensated by recovering the Cr magnetic moment. Our analysis suggests that PMA is caused by interfacial exchange coupling between ferromagnetic Fe0.6Al0.4 and antiferromagnetic Cr0.8Al0.2.

Long-Range Influence of Cr on the Stacking Fault Energy of Cr-Containing Concentrated Solid-Solution Alloys

Single-phase concentrated solid-solution alloys (CSAs) have exhibited excellent mechanical and radiation tolerance properties, making them potential candidate materials for nuclear applications. These excellent properties are closely related to dislocation movements, which depend on the stacking fault energies (SFEs). In CSAs, SFEs show large fluctuations due to variations in the local atomic environments in the vicinity of the stacking faults. In this work, first-principle calculations were performed to investigate the origin of the fluctuations in the SFEs of the widely studied CSA, NiCoCr, which show a very wide distribution from about −200 mJ/m2 to 60 mJ/m2. Compared to the common understanding that only atoms in close proximity to the stacking fault influence the SFEs in pure metals and dilute alloys, charge redistribution can be observed in several nearby planes of the stacking fault in NiCoCr, indicating that atoms several atomic layers away from stacking fault also contribute to the SFEs. Our analysis shows that Cr plays a major role in the large fluctuation in the SFEs of NiCoCr based on both electronic and magnetic responses. The flexible electronic structure of Cr facilitates easier charge transfer with Cr in several nearby atomic planes near the stacking fault, leading to significant changes in the d-electron number, orbital occupation number, and magnetic moments of Cr.

Magnetism of single-doped paramagnetic tin clusters studied using temperature-dependent Stern-Gerlach experiments with enhanced sensitivity: impact of the diamagnetic ligand field and paramagnetic dopant.

In this work, the magnetic properties of tetrel clusters SnNTM, which are singly doped with transition metals (TM), are investigated. On the one hand, the number of tetrel atoms (N = 11, 12, 14 and 17 with TM = Mn) is varied; on the other hand, different transition metals (N = 14, TM = Cr, Mn, Fe) are studied. Magnetic deflection experiments under cryogenic conditions show that the variation of the number of tetrel atoms strongly changes the magnetic properties of the Mn-doped clusters. It is observed that Sn12Mn, Sn11Mn and Sn14Mn partially show super-atomic behaviour, while spin relaxation occurs in Sn17Mn. Magnetic deflection experiments at higher nozzle temperatures were carried out for the first time enhanced by a second parallel-aligned Stern-Gerlach magnet to achieve larger deflections. The resulting temperature-dependent one-sided deflections are quantitatively analysed using Curie's law and show that Sn17Mn possesses the highest magnetic moment of these clusters, followed by Sn12Mn and Sn11Mn. Sn14Mn shows the lowest magnetic moment. The replacement of Mn by Cr in Sn14Mn leads to a diamagnetic singlet, i.e., the magnetic moment of Cr in Sn14Cr is completely quenched. The replacement of Mn by Fe in turn leads to a paramagnetic species, whereby Sn14Fe is most likely present as a triplet. On this basis, the geometrical and electronic structures are analysed using quantum chemical calculations, indicating an arachno-type structure for Sn14Cr, Sn14Mn and Sn14Fe, which has already been predicted in the literature for Si14Cr. This is experimentally confirmed by deflection of molecular beams with an electric field under cryogenic conditions, suggesting that the arachno-type geometry is crucial for the overall stability of the transition-metal-doped tetrel clusters Sn14TM with TM = Cr, Mn, Fe.

Magnetic properties and muon localization in Cr2S3

We investigate the magnetic ground state of rhombohedral chromium sulphide Cr2S3 by density functional theory. We identify the muon implantation sites, their hyperfine couplings and the role of charge states in this compound. Our calculations show that we can obtain a compensated ferrimagnetic ground state. We find that strong electronic correlations are required to correctly obtain the semiconducting band behaviour of Cr2S3 in agreement with experiment. Relying on earlier µSR measurements, our calculations suggest that the two muon local fields in Cr2S3 are due to distinct charge states for two very close but distinct muon sites bonded between two sulphur atoms. Further analysis of the static field at the muon allows to determine by µSR the average Cr magnetic moment in good agreement with experiment.

Discovery of ferromagnetism in new multicomponent alloy Ti–Nb–Cr–Ru

We report the discovery of ferromagnetism in the cubic CsCl-type Ti21∼25Nb20∼24Cr5∼10Ru∼49 multicomponent alloy. In metals, the appearance of ferromagnetism due to the Cr magnetic moment is a rare phenomenon. The purest sample shows ferromagnetism with the Curie temperature of 38 K. The effective magnetic moment and the Weiss temperature are 3.67 μB/Cr and 58 K, respectively, derived from the temperature dependence of dc magnetization. These values mean the ferromagnetic exchange interaction between the localized Cr magnetic moments. The ferromagnetic nature is also confirmed by the isothermal magnetization curve with the highest magnetization of 1.1 μB/Cr at 2 K. The electronic structure calculation also supports a ferromagnetic ground state in the CsCl-type structure. We further investigated the effect of elemental substitution on the ferromagnetic behavior. The partial substitution of Pd for Ru heavily suppresses the Curie temperature, indicating that the Ru atom may play an essential role in sustaining ferromagnetism. Ti21∼25Nb20∼24Cr5∼10Ru∼49 would be the first example of the ferromagnetic Cr-containing multicomponent alloy, and this study shows the usefulness of the large compositional space in exploring novel phenomena.

Electronic, Magnetic, and Optical Properties of Metal Adsorbed g-ZnO Systems

2D ZnO is one of the most attractive materials for potential applications in photocatalysis, gas and light detection, ultraviolet light-emitting diodes, resistive memory, and pressure-sensitive devices. The electronic structures, magnetic properties, and optical properties of M (Li, Na, Mg, Ca, or Ga) and TM (Cr, Co, Cu, Ag, or Au) adsorbed g-ZnO were investigated with density functional theory (DFT). It is found that the band structure, charge density difference, electron spin density, work function, and absorption spectrum of g-ZnO can be tuned by adsorbing M or TM atoms. More specifically, the specific charge transfer occurs between g-ZnO and adsorbed atom, indicating the formation of a covalent bond. The work functions of M adsorbed g-ZnO systems are obviously smaller than that of intrinsic g-ZnO, implying great potential in high-efficiency field emission devices. The Li, Na, Mg, Ca, Ga, Ag, or Au adsorbed g-ZnO systems, the Cr adsorbed g-ZnO system, and the Co or Cu adsorbed g-ZnO systems exhibit non-magnetic semiconductor proprieties, magnetic semiconductor proprieties, and magnetic metal proprieties, respectively. In addition, the magnetic moments of Cr, Co, or Cu adsorbed g-ZnO systems are 4 μ B, 3 μ B, or 1 μ B, respectively, which are mainly derived from adsorbed atoms, suggesting potential applications in nano-scale spintronics devices. Compared with the TM absorbed g-ZnO systems, the M adsorbed g-ZnO systems have more obvious absorption peaks for visible light, particularly for Mg or Ca adsorbed g-ZnO systems. Their absorption peaks appear in the near-infrared region, suggesting great potential in solar photocatalysis. Our work contributes to the design and fabrication of high-efficiency field emission devices, nano-scale spintronics devices, and visible-light responsive photocatalytic 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.

Study on FeCr thin film for a spintronic material with negative spin polarization

Negative spin polarization materials generate a spin current whose spin direction is opposite to the magnetization direction. This characteristic is technologically important because it increases the freedom in the design of spintronic devices. In this paper, we studied FeCr from the viewpoints of band structure, atomic magnetic moments, and local atomic arrangement to explore its potentiality as a negative spin polarization material. First-principles calculations on the disordered FeCr alloy predicted a high negative spin polarization, which was attributed to the band matching of the minority spin. We experimentally fabricated Fe1-xCrx thin films in the Cr concentration (x) range from 0.2 to 0.4 by sputter deposition and demonstrated inverse magnetoresistance using current-perpendicular-to-plane giant magnetoresistance (GMR) devices, which provided evidence of negative spin polarization. The spin polarization of Fe0.7Cr0.3 estimated from the GMR device measurements was −0.28 and fell below the calculated value. Synchrotron X-ray magnetic circular dichroism measurements showed a ferrimagnetic configuration of the Fe and Cr magnetic moments. The Fe moment showed a large moment over a wide Cr concentration range, whereas the Cr moment decreased with the Cr concentration, which agreed with the calculation result. Synchrotron Mössbauer spectroscopy measurements indicated the inhomogeneity of the FeCr composition even in the as-deposited state. Fe-rich regions were formed after annealing, reflecting the phase separation nature of the Fe-Cr system. Inhomogeneity was not considered in the calculation and could be the origin of the smaller negative spin polarization observed in the experiment.

Structural, Electronic, and Physical Properties of a New Layered Cr-Based Oxyarsenide Sr2Cr2AsO3.

We report synthesis, crystal structure, and physical properties of SrCrAsO. The new compound crystallizes in a SrGaOCuS-type structure with two distinct Cr sites, Cr(1) in the perovskite-like block layers of “SrCrO” and Cr(2) in the ThCrSi-type layers of “SrCrAs”. An inter-block-layer charge transfer is explicitly evidenced, which dopes electrons in the CrO planes and simultaneously dopes holes into the CrAs layers. Measurements of electrical resistivity, magnetization, and specific heat, in combination with density-functional theoretical calculations, indicate that the title material is an antiferromagnetic metal. The Cr(2) magnetic moments in the CrAs layers order at 420 K, while the Cr(1) spins in the CrO planes show quasi-two-dimensional magnetism with long-range ordering below 80 K. Both Néel temperatures are significantly reduced, compared with those of the cousin material SrCrAsO, probably due to the intrinsic charge-carrier doping. Complex re-entrant magnetic transitions with a huge magnetic hysteresis were observed at low temperatures.

Magnetocaloric, electronic, magnetic, optical and thermoelectric properties in antiferromagnetic semiconductor GdCrO3: Monte Carlo simulation and density functional theory

Density functional theory and Monte Carlo simulation are performed on the magnetocaloric, electronic, optical, thermoelectric and magnetic properties of GdCrO3. The density of states diagrams is discussed. The values of the exchange energy calculated between the magnetic configurations Gd and Cr atoms was calculated. The GdCrO3 has semiconductor character and antiferromagnetic behavior. The dielectric function, absorption and reflectivity are also investigated. The thermoelectric response is evaluated by calculating electrical conductivity, thermal conductivity and seebeck coefficient (S) by using BoltzTraP code. The magnetic moment of Cr and Gd are calculated. The Néel temperature has been obtained. The presence of spin reorientation transition is also observed in this system. The maximum magnetic entropy change and relative cooling power are found to be respectively, 2.64 J.K−1.kg−1 and 25 J.kg−1 for h = 5 T.

Study of the Structure, Magnetic, Thermal and Electrical Characterisation of ZnCr2Se4: Ta Single Crystals Obtained by Chemical Vapour Transport.

The new series of single-crystalline chromium selenides, Ta-doped ZnCr2Se4, was synthesised by a chemical vapour transport method to determine the impact of a dopant on the structural and thermodynamic properties of the parent compound. We present comprehensive investigations of structural, electrical transport, magnetic, and specific heat properties. It was expected that a partial replacement of Cr ions by a more significant Ta one would lead to a change in direct magnetic interactions between Cr magnetic moments and result in a change in the magnetic ground state and electric transport properties of the ZnCr2−xTaxSe4 (x = 0.05, 0.06, 0.07, 0.08, 0.1, 0.12) system. We found that all the elements of the cubic system had a cubic spinel structure; however, the doping gain linearly increased the ZnCr2−xTaxSe4 unit cell volume. Doping with tantalum did not significantly change the semiconductor and magnetic properties of ZnCr2Se4. For all studied samples (0 ≤ x ≤ 0.12), an antiferromagnetic order (AFM) below TN~22 K was observed. However, a small amount of Ta significantly reduced the second critical field (Hc2) from 65 kOe for x = 0.0 (ZnCr2Se4 matrix) up to 42.2 kOe for x = 0.12, above which the spin helical system changed to ferromagnetic (FM). The Hc2 reduction can lead to strong competition among AFM and FM interactions and spin frustration, as the specific heat under magnetic fields H < Hc2 shows a strong field decrease in TN.

Non-Fermi liquid behavior and signature of Griffiths phase in Ni–Cr binary alloy

Detailed magnetic, electrical, and thermal property measurements have been carried out on Ni100−xCrx binary alloys, mainly to study the effect of Cr. The following points emerge from this study: with the increase in Cr concentration, magnetic moment and Curie temperature linearly decreased and the ferromagnetic order is completely suppressed at the critical concentration (xcr ≈ 12.16 ± 0.03). The Rhodes–Wohlfarth ratio increases as the concentration approaches xcr, suggesting a weak itinerant ferromagnetic character of NiCr compositions (x &amp;lt; xcr). Analysis of low-temperature electrical resistivity and specific heat data suggests that the spin fluctuation’s contribution increases and the Fermi-liquid behavior breaks down as the concentration approaches xcr. For x ∼ xcr, the dc susceptibility χ(T) deviates from the Curie–Weiss law reminiscent to that of the Griffiths phase. The low-temperature magnetic isotherms of Ni–Cr follow power law, M(H)=M0+dλHλ, and the non-universal exponent (λ) shows a minimum at xcr ∼ 12. Further, temperature dependence of magnetization studies also support the presence of the quantum Griffiths phase, similar to that reported in the Ni–V alloy system. The temperature dependencies of the electrical resistivity, magnetization, and specific heat follow the theoretical predictions of a quantum critical point within experimental uncertainties.

Thermal decomposition of GdCrO4 to GdCrO3: Structure and magnetism

Rare-earth orthochromites (RCrO3) with orthorhombically distorted perovskite (ABO3) structure exhibit a wealth of magnetic phenomena including temperature-induced magnetization reversal (TMR), spin-reorientation (SR), spin-flipping (SF) and exchange-bias (EB). These occur as a result of magnetic interactions among the cations such as Cr3+–Cr3+, Cr3+–R3+ and R3+–R3+, where R is the rare earth element. In the present work, GdCrO4 samples were prepared using the sol-gel technique. The as-synthesized samples are amorphous in nature. Calcination of the samples at 600 °C for 1 h leads to the formation of the GdCrO4 phase whereas increasing the calcination temperature to 1000 °C for 1 h triggers the decomposition of GdCrO4 into GdCrO3. The role of thermal decomposition of GdCrO4 to GdCrO3 on crystal structure and magnetic transitions are discussed in this paper. Microstructure analyses show that the GdCrO4 powders have an intercalated porous structure that comprises a core-shell like construction with undistinguishable grain boundaries, whereas the morphology of the GdCrO3 demonstrates bulk nature with particles having micrometer size. Magnetization measurements as a function of temperature (M-T) with different probing magnetic fields show the ferromagnetic Curie temperature, (TC), of the GdCrO4 sample to be 24 K. GdCrO3 orders antiferromagnetically with a Néel temperature, TN (Cr), ascribed to the Cr magnetic moment at 171 K. A spin-flip transition (TSF) occurred at 22 K indicating the flipping of Cr3+ and Gd3+ spins and the spin-reorientation (TSR) transition is located at 5 K. The hysteresis loops measured across the transition temperatures validate the magnetic transitions as observed in the M-T curves.

L10 -ordered (Fe100−xCrx)Pt thin films: Phase formation, morphology, and spin structure

Chemically ordered $L{1}_{0}$ $({\mathrm{Fe}}_{100\ensuremath{-}x}{\mathrm{Cr}}_{x})\mathrm{Pt}$ thin films were expitaxially grown on MgO(001) substrates by magnetron sputter-deposition at $770{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$. In this sample series, Fe was continuously substituted by Cr over the full composition range. The lattice parameter in the [001] growth direction steadily increases from $L{1}_{0}$-FePt toward $L{1}_{0}$-CrPt, confirming the incorporation of Cr in the lattice occupying Fe sites. With the observed high degree of chemical ordering and (001) orientation, strong perpendicular magnetic anisotropy is associated, which persists up to a Cr content of $x=20$ at. %. Similarly, the coercive field in the easy-axis direction is strongly reduced, which is, however, further attributed to a strong alteration of the film morphology with Cr substitution. The latter changes from a well-separated island microstructure to a more continuous film morphology. In the dilute alloy with low Cr content, isolated Cr magnetic moments couple antiferromagnetically to the ferromagnetic Fe matrix. In this case, all Cr moments are aligned parallel, thus forming a ferrimagnetic FeCrPt system. With increasing Cr concentration, nearest-neighbor Cr-Cr pairs start to appear, thereby increasing magnetic frustration and disorder, which lead to canting of neighboring magnetic moments, as revealed by atomistic spin-model simulations with model parameters based on first principles. At higher Cr concentrations, a frustrated ferrimagnetic order is established. With Cr substitution of up to 20 at. %, no pronounced change in Curie temperature, which is in the range of 700 K, was noticed. But with further addition the Curie temperature drops down substantially even down to room temperature at 47 at. % Cr. Furthermore, x-ray magnetic circular dichroism studies on dilute alloys containing up to 20 at. % of Cr revealed similar spin moments for Fe and Cr in the range between 2.1--2.5 ${\ensuremath{\mu}}_{B}$ but rather large orbital moments of up to 0.50 $\ifmmode\pm\else\textpm\fi{}0.10\phantom{\rule{4pt}{0ex}}{\ensuremath{\mu}}_{B}$ for Cr. These results were also compared to ab initio calculations.

Magnetic profile of proximity-coupled (Dy,Bi)2Te3/(Cr,Sb)2Te3 topological insulator heterostructures

Magnetic topological insulators (TIs) are an ideal playground for the study of novel quantum phenomena building on time-reversal symmetry-broken topological surface states. By combining different magnetic TIs in a heterostructure, their magnetic and electronic properties can be precisely tuned. Recently, we have combined high-moment $\mathrm{Dy}:{\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ with high transition temperature $\mathrm{Cr}:{\mathrm{Sb}}_{2}{\mathrm{Te}}_{3}$ in a superlattice, and we found, using x-ray magnetic circular dichroism (XMCD), that long-range magnetic order can be introduced in the $\mathrm{Dy}:{\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ layers. Accompanying first-principles calculations indicated that the origin of the long-range magnetic order is a strong antiferromagnetic coupling between Dy and Cr magnetic moments at the interface extending over several layers. However, based on XMCD alone, which is either averaging over the entire thin-film stack or is surface-sensitive, this coupling scenario could not be fully confirmed. Here we use polarized neutron reflectometry, which is ideally suited for the detailed study of superlattices, to retrieve the magnetization in a layer- and interface-resolved way. We find that the magnetization is, in contrast to similar recent studies, homogeneous throughout the individual layers, with no apparent interfacial effects. This finding demonstrates that heterostructure engineering is a powerful way of controlling the magnetic properties of entire layers, with the effects of coupling reaching beyond the interface region.

Chromium Influenced High Magnetic Moment and Half-Metallic Nature of GaN Nanotube.

Density functional theory-based calculations have been performed to analyze the electronic and magnetic properties of chromium doped (6, 0) GaN nanotube. The structural stability of GaN nano-tube has been defined in terms of formation energy, which increases as a function of magnetic impurity (Cr). The study demonstrates that the direct band gap semiconducting GaN nanotube transforms to half-metallic as a function of Cr introduction to GaN. This half metallic nature with high magnetic moment of Cr doped GaN nanotube can be a key parameter for its use in spintronics applications.

Structural and magnetic response of CrI3 monolayer to electric field

A recent theoretical study reported large structural response to perpendicular electric fields in monolayer CrI3, which could be related to the microscopic origin of the technologically promising and experimentally observed electrical switching of magnetization in bilayer CrI3. However, these theoretical results are contrary to a previous theoretical finding of only slight changes under a strong electric field in CrI3. Here, we investigate the effects of perpendicular electric fields on the CrI3 monolayer using density-functional theory for various field strengths. Conclusively, we find an extremely small structural response to the electric field, due to a very efficient electronic screening of the field within the monolayer. Therefore, it cannot be the origin of the observed electrical switching of magnetization in the bilayer CrI3. Furthermore, we find the linear-response trends of the weak structural changes to persist up to a field value of 0.45 V/Å, in which range the Cr magnetic moment remains constant.

Magnetic Moments and Electron Transport through Chromium-Based Antiferromagnetic Nanojunctions.

We report the electronic, magnetic and transport properties of a prototypical antiferromagnetic (AFM) spintronic device. We chose Cr as the active layer because it is the only room-temperature AFM elemental metal. We sandwiched Cr between two non-magnetic metals (Pt or Au) with large spin-orbit coupling. We also inserted a buffer layer of insulating MgO to mimic the structure and finite resistivity of a real device. We found that, while spin-orbit has a negligible effect on the current flowing through the device, the MgO layer plays a crucial role. Its effect is to decouple the Cr magnetic moment from Pt (or Au) and to develop an overall spin magnetization. We have also calculated the spin-polarized ballistic conductance of the device within the Büttiker–Landauer framework, and we have found that for small applied bias our Pt/Cr/MgO/Pt device presents a spin polarization of the current amounting to ≃25%.

Neutron diffraction study on magnetic structures and transitions in Sr2Cr3As2O2

Sr2Cr3As2O2 is composed of alternating square-lattice CrO2 and Cr2As2 stacking layers, where CrO2 is isostructural to the CuO2 building-block of cuprate high-Tc superconductors and Cr2As2 to Fe2As2 of Fe-based superconductors. Current interest in this material is raised by theoretic prediction of possible superconductivity. In this neutron powder diffraction study, we discovered that magnetic moments of Cr(II) ions in the Cr2As2 sublattice develop a C-type antiferromagnetic structure below 590 K, and the moments of Cr(I) in the CrO2 sublattice form the La2CuO4 -like antiferromagnetic order below 291 K. The staggered magnetic moment 2.19(4){\mu} B /Cr(II) in the more itinerant Cr2As2 layer is smaller than 3.10(6){\mu}_B/Cr(I) in the more localized CrO2 layer. Different from previous expectation, a spin-flop transition of the Cr(II) magnetic order observed at 291 K indicates a strong coupling between the CrO2 and Cr2As2 magnetic subsystems.