Neutron diffraction study on magnetic structures and transitions in 
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Liu, Juanjuan; Wang, Jinchen; Sheng, Jieming; Ye, Feng; Taddei, Keith M.; Fernandez-Baca, J. A.; Luo, Wenjun; Sun, Guangai; Wang, Zhicheng; Jiang, Hao; Cao, Guanghan; Bao, Wan-Su

doi:10.1103/physrevb.98.134416

Cited by 9 publications

(43 citation statements)

References 55 publications

(54 reference statements)

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“…This increases rapidly on cooling and overtakes the magnitude of the Cr(2) (arsenide layer) moments by 248 K. Between these temperatures, a gradual reorientation of the direction of both sets of moments takes place in Sr2CrO2Cr2As2: the Cr(1) moments in the oxide layer rotate from the ab-plane to lie along the c-axis, and the Cr(2) moments in the arsenide layer rotate vice versa. This behaviour of Sr2CrO2Cr2As2 has recently been reported by Liu et al 13 and our results are consistent with theirs. We note here that our PND measurements in this reorientation region straddling room temperature were measured on warming in the cryostat which was not optimised for controlling temperature or measuring the sample temperature in this range.…”

Section: Resultssupporting

confidence: 94%

“…However the details of these magnetic models are different in Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2, and in particular the magnetic scattering of Sr2CrO2Cr2As2 shows some anomalies as described below which have not been observed previously. 13 In Ba2CrO2Cr2As2 the fits to the data below 233 K (Figure 5 In Sr2CrO2Cr2As2 the magnitude of the Cr(1) (oxide layer) ordered moment at 297 K is 1.61(1) μB. This increases rapidly on cooling and overtakes the magnitude of the Cr(2) (arsenide layer) moments by 248 K. Between these temperatures, a gradual reorientation of the direction of both sets of moments takes place in Sr2CrO2Cr2As2: the Cr(1) moments in the oxide layer rotate from the ab-plane to lie along the c-axis, and the Cr(2) moments in the arsenide layer rotate vice versa.…”

Section: Resultsmentioning

confidence: 99%

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Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr₂CrO₂Cr₂As₂ and Ba₂CrO₂Cr₂As₂

Jones

Cassidy

et al. 2020

Inorg. Chem.

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Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2 with Cr 2+ ions in CrO2 sheets and in CrAs layers crystallize with the Sr2Mn3Sb2O2 structure (space group I4/mmm, Z = 2) and lattice parameters a = 4.00800(2) Å, c = 18.8214(1) Å ( Sr2CrO2Cr2As2) and a = 4.05506(2) Å, c = 20.5637(1) Å (Ba2CrO2Cr2As2) at room temperature. Powder neutron diffraction reveals checkerboard-type antiferromagnetic ordering of the Cr 2+ ions in the arsenide layers below TN1_Sr, of 600(10) K (Sr2CrO2Cr2As2) and TN1_Ba 465(5) K (Ba2CrO2Cr2As2) with the moments initially directed perpendicular to the layers in both compounds.Checkerboard-type antiferromagnetic ordering of the Cr 2+ ions in the oxide layer below 230(5) K for Ba2CrO2Cr2As2 occurs with these moments also perpendicular to the layers, consistent with the orientation preferences of d 4 moments in the two layers. In contrast, below 330(5) K in Sr2CrO2Cr2As2 the oxide layer Cr 2+ moments are initially oriented in the CrO2 plane, but on further cooling these moments rotate to become perpendicular to the CrO2 planes, while the moments in the arsenide layers rotate by 90° with the moments on the two sublattices remaining orthogonal throughout [behavior recently reported independently by Liu et al. Phys. Rev. B 2018, 98, 134416]. In Sr2CrO2Cr2As2 electron diffraction and high resolution powder X-ray diffraction data show no evidence for a structural distortion that would allow the two Cr 2+ sublattices to couple, but high resolution neutron powder diffraction data suggest a small incommensurability between the magnetic structure and the crystal structure, which may account for the coupling of the two sublattices and the observed spin reorientation. The saturation values of the Cr 2+ moments in the CrO2 layers (3.34(1) B (for Sr2CrO2Cr2As2) and 3.30(1) B (for Ba2CrO2Cr2As2)) are larger than those in the CrAs layers (2.68(1) B for Sr2CrO2Cr2As2 and 2.298(8) B for Ba2CrO2Cr2As2) reflecting greater covalency in the arsenide layers.

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Section: Resultssupporting

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr₂CrO₂Cr₂As₂ and Ba₂CrO₂Cr₂As₂

Jones

Cassidy

et al. 2020

Inorg. Chem.

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“…The superexchange interactions would therefore appear to be very delicately balanced in the Sr2M3As2O2 phases 9,11,12,14,15 . In Sr2Mn3-xCrxAs2O2 the magnetic coupling between the M(1)O2 2-planes and the M(2)2As2 2slabs gets stronger as the Cr concentration increases from x = 0 -3 so that the antiferromagnetic ordering temperatures increase from 0 K -340 K (M(1)O2 2- The temperature dependence of the magnetic susceptibility, for Sr2Mn2.23Cr0.77As2O2 is shown in The thermal variation of the electrical resistivity is displayed in Figure 10 which indicates that Sr2Mn2.23Cr0.77As2O2 is a semiconductor.…”

Section: Resultsmentioning

confidence: 99%

“…Sr2Cr3As2O2 has recently been synthesised 11,12 , and is isostructural with Sr2Mn3As2O2; containing As were mixed with non-stoichiometric amounts of SrO with a 2% wt. deficiency.…”

Section: Introductionmentioning

confidence: 99%

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Electronic and Magnetic Properties of Cation Ordered Sr₂Mn_2.23Cr_0.77As₂O₂

et al. 2020

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Several different mechanisms of magnetoresistance (MR) have been observed in 1111 LnMnAsO1-xFx oxypnictides (Ln = lanthanide) as a result of magnetic coupling between the Mn and Ln. Such phases also exhibit interesting magnetic phase transitions upon cooling. Sr2Mn2CrAs2O2 has been synthesised in order to investigate if it's possible to observe MR and/or magnetic phase transitions as a result of magnetic coupling between the Mn and Cr. Sr2Mn2CrAs2O2 crystallises with the I4/mmm tetragonal space group containing alternating MO2 2and M'2As2 2layers and neutron diffraction results demonstrate that the actual stoichiometry is Sr2Mn2.23Cr0.77As2O2. Cation order is present between Mn and Cr, with Cr predominantly occupying the square planar MO2 2site. Below 410 K the magnetic moments of the Mn/Cr ions in the M'2As2 2sublattice exhibit G-type antiferromagnetic order. The Mn/Cr moments within the MO2 2layer order below 167 K with a K2NiF4-typeantiferromagnetic structure which simultaneously induces a spin-flip of the magnetic moments in the M'2As2 2layers from a G-to C-type antiferromagnetic arrangement. The results demonstrate that the 2 superexchange interactions are finely balanced in Sr2Mn2.23Cr0.77As2O2. Sr2Mn2.23Cr0.77As2O2 is semiconducting and there is no evidence of MR. type antiferromagnetic arrangement. Electron doping of the M'2As2 2slabs is warranted to investigate this further. ASSOCIATED CONTENTSupporting Information. The supporting information includes Rietveld fits from neutron diffraction and synchrotron X-ray diffraction data and tables of crystallographic data.

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Quasi-Two-Dimensional Heterostructures (KM_1 – xTe)(LaTe₃) (M = Mn and Zn) with Charge Density Waves

et al. 2021

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Layered heterostructure materials with two different functional building blocks can teach us about emergent physical properties and phenomena arising from interactions between the layers. We report intergrowth compounds KLaM 1 − x Te 4 (M = Mn and Zn; x ≈ 0.35) featuring two chemically distinct alternating layers [LaTe 3 ] and [KM 1 − x Te]. Their crystal structures are incommensurate, determined by single X-ray diffraction for the Mn compound and a transmission electron microscope study for the Zn compound. KLaMn 1 − x Te 4 crystallizes in the orthorhombic superspace group Pmnm(01/2γ)s00 with lattice parameters a = 4.4815(3) Å, b = 21.6649(16) Å, and c = 4.5220(3) Å. It exhibits charge density wave order at room temperature with a modulation wave vector q = 1/2b* + 0.3478c* originating from electronic instability of Te-square nets in [LaTe 3 ] layers. The Mn analog exhibits a cluster spin glass behavior with spin freezing temperature T f ≈ 5 K attributed to disordered Mn vacancies and competing magnetic interactions in the [Mn 1 − x Te] layers. The Zn analog also has charge density wave order at room temperature with a similar q-vector having the c* component ∼0.346 confirmed by selected-area electron diffraction. Electron transfer from [KM 1 − x Te] to [LaTe 3 ] layers exists in KLaM 1 − x Te 4 , leading to an enhanced electronic specific heat coefficient. The resistivities of KLaM 1 − x Te 4 (M = Mn and Zn) exhibit metallic behavior at high temperatures and an upturn at low temperatures, suggesting partial localization of carriers in the [LaTe 3 ] layers with some degree of disorder associated with the M atom vacancies in the [M 1 − x Te] layers.

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Neutron diffraction study on magnetic structures and transitions in Sr2Cr3As2O2

Cited by 9 publications

References 55 publications

Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr₂CrO₂Cr₂As₂ and Ba₂CrO₂Cr₂As₂

Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr₂CrO₂Cr₂As₂ and Ba₂CrO₂Cr₂As₂

Electronic and Magnetic Properties of Cation Ordered Sr₂Mn_2.23Cr_0.77As₂O₂

Quasi-Two-Dimensional Heterostructures (KM_1 – xTe)(LaTe₃) (M = Mn and Zn) with Charge Density Waves

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Neutron diffraction study on magnetic structures and transitions in Sr2Cr3As2O2

Cited by 9 publications

References 55 publications

Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2

Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2

Electronic and Magnetic Properties of Cation Ordered Sr2Mn2.23Cr0.77As2O2

Quasi-Two-Dimensional Heterostructures (KM1 – xTe)(LaTe3) (M = Mn and Zn) with Charge Density Waves

Contact Info

Product

Resources

About

Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr₂CrO₂Cr₂As₂ and Ba₂CrO₂Cr₂As₂

Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr₂CrO₂Cr₂As₂ and Ba₂CrO₂Cr₂As₂

Electronic and Magnetic Properties of Cation Ordered Sr₂Mn_2.23Cr_0.77As₂O₂

Quasi-Two-Dimensional Heterostructures (KM_1 – xTe)(LaTe₃) (M = Mn and Zn) with Charge Density Waves