Redetermination the basic cell trigonal Cr5Te8 single crystal structure and its temperature dependence Raman spectra

Fu, Boyang; Bao, Xinjian; Deng, Haibin; Zhang, Min

doi:10.1016/j.jssc.2021.122222

Cited by 7 publications

(10 citation statements)

References 23 publications

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“…Figure S3a shows the X-ray diffraction (XRD) pattern of Cr 2 Te 3 nanosheets, again confirming the single crystalline and hexagonal crystal structure (PDF 29-0458) . Additionally, Raman spectrum of Cr 2 Te 3 nanosheet (Figure S3b) shows two characteristic peaks at 122.1 and 139.3 cm –1 , which is consistent with the previously reported results . To investigate the magnetic properties of the CVD-synthesized Cr 2 Te 3 nanosheets, we measured the magnetization using VSM from a physical property measurement system (PPMS).…”

supporting

confidence: 86%

“…30 Additionally, Raman spectrum of Cr 2 Te 3 nanosheet (Figure S3b) shows two characteristic peaks at 122.1 and 139.3 cm −1 , which is consistent with the previously reported results. 31 To investigate the magnetic properties of the CVD-synthesized Cr 2 Te 3 nanosheets, we measured the magnetization using VSM from a physical property measurement system (PPMS). Figure 1f shows the field cooling (FC) and zero field cooling (ZFC) magnetization versus temperature (M−T) curves of Cr 2 Te 3 nanosheets, clearly showing the FM behavior with a T C around 200 K. 26 Moreover, Figure 1g shows the corresponding magnetization versus magnetic field (M−H) curves measured at different temperatures ranging from 5 to 300 K. Obvious hysteresis can be found with the temperature below 200 K (T C ) with a distinguished coercivity of 0.52 T for 5 K (top left inset of Figure 1g).…”

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confidence: 99%

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Field-Free Improvement of Oxygen Evolution Reaction in Magnetic Two-Dimensional Heterostructures

Xiong

Luo

et al. 2021

Nano Lett.

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Ferromagnetic (FM) electrocatalysts have been demonstrated to reduce the kinetic barrier of oxygen evolution reaction (OER) by spin-dependent kinetics and thus enhance the efficiency fundamentally. Accordingly, FM two-dimensional (2D) materials with unique physicochemical properties are expected to be promising oxygen-evolution catalysts; however, related research is yet to be reported due to their air-instabilities and low Curie temperatures (T C). Here, based on the synthesis of 2D air-stable FM Cr2Te3 nanosheets with a low T C around 200 K, room-temperature ferromagnetism is achieved in Cr2Te3 by proximity to an antiferromagnetic (AFM) CrOOH, demonstrating the accomplishment of long-ranged FM ordering in Cr2Te3 because the magnetic proximity effect stems from paramagnetic (PM)/AFM heterostructure. Therefore, the OER performance can be permanently promoted (without applied magnetic field due to nonvolatile nature of spin) after magnetization. This work demonstrates that a representative PM/AFM 2D heterostructure, Cr2Te3/CrOOH, is expected to be a high-efficient magnetic heterostructure catalysts for oxygen-evolution.

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confidence: 86%

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confidence: 99%

Field-Free Improvement of Oxygen Evolution Reaction in Magnetic Two-Dimensional Heterostructures

Xiong

Luo

et al. 2021

Nano Lett.

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“…The softening of vibrational modes can be attributed to long-range lattice disorder . Temperature-induced mode softening has been reported in Cr 5 Te 8 . Pressure dependence of the A 1g mode indicates that lattices of Cr 1−δ Te become more disordered with increasing pressure.…”

Section: Resultsmentioning

confidence: 95%

“…37 Temperature-induced mode softening has been reported in Cr 5 Te 8 . 38 decreases by only 1 order of magnitude with increasing pressure, and a turning point appears at 9.3 GPa. Pressuredependent resistivity of Cr 5 Te 8 exhibits an unusual change, that is, the resistivity has a local minimum value at 10.7 GPa, then increases with compression, and starts to decrease again at 20.5 GPa.…”

Section: ■ Experimental Sectionmentioning

confidence: 94%

Pressure-Induced Structural Phase Transition, Anomalous Insulator-to-Metal Transition, and n–p Conduction-Type Switching in Defective, NiAs-Type Cr_1−δTe

Liu

Jin

et al. 2022

Inorg. Chem.

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Cr1−δTe, as a unique series of defective compounds with a NiAs-type structure and periodic metal vacancies, has attracted intensive research interest because of its diversity in structure and property dependent on the tunable stoichiometric ratio. Another feature of these compounds is their ability to switch between NiAs- and MnP-type structures, in which there often exist composition-, temperature-, or pressure-induced phase transitions accompanied by intriguing physical property switching. Herein, we report the syntheses of a series of Cr1−δTe compounds with similar compositions but distinct crystal structures, their phase transitions, anomalous transport, and photoelectric conduction behaviors under high pressure (HP). For the three Cr1−δTe compounds with δ = 0, 0.25, 0.375, CrTe undergoes pressure-induced NiAs-to-MnP phase transition at around 15 GPa, while Cr3Te4 and Cr5Te8 undergo isostructural phase transitions at around 12 and 11 GPa, respectively. Electrical transport measurements indicate anomalous conduction behaviors: CrTe undergoes a semiconductor-to-metal transition at around 24 GPa, while Cr3Te4 and Cr5Te8 show unexpected metal–semiconductor–metal transitions sequentially upon compression. Besides, CrTe and Cr5Te8 exhibit pressure-induced n–p conduction-type switching at around 9 and 3 GPa, respectively, while Cr3Te4 shows p-type conductivity in the full pressure range. Local structure analyses based on in situ HP Raman spectra are performed to understand the structure and property evolutions of Cr1−δTe under HP. Defective transition-metal chalcogenides with pressure-induced NiAs-to-MnP phase transition and conduction-type conversion provide a potential platform for the rational design of photoelectric conversion devices.

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“…Some of these new peaks (114.0 cm −1 , 127.4 cm −1 , 145.0 cm −1 ) have already been reported for a Cr-Te compound whose composition was estimated, based on a basic analysis of the relative intensity of peaks appearing in EDS, to 5:8. 43 Our Raman spectroscopy data hence shows that annealing pogressively transforms 1T -CrTe 2 into a compound that could be Cr 5 Te 8 (see sketches of the structure in Figure 1).…”

Section: Thermally-induced Transformation Of 1t -Crtementioning

confidence: 67%

Stability of the In-Plane Room Temperature van der Waals Ferromagnet Chromium Ditelluride and Its Conversion to Chromium-Interleaved CrTe$_2$ Compounds

Purbawati,

Sarkar,

Pairis

et al. 2023

Preprint

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Van der Waals magnetic materials are building blocks for novel kinds of spintronic devices and playgrounds for exploring collective magnetic phenomena down to the twodimensional limit. Chromium-tellurium compounds are relevant in this perspective. In particular, the 1T phase of CrTe 2 has been argued to have a Curie temperature above 300 K, a rare and desirable property in the class of lamellar materials, making it a candidate for practical applications. However, recent literature reveals a strong variability in the reported properties, including magnetic ones. Using electron microscopy, diffraction and spectroscopy techniques, together with local and macroscopic magnetometry approaches, our work sheds new light on the structural, chemical and magnetic properties of bulk 1T -CrTe 2 exfoliated in the form of flakes having a thickness ranging from few to several tens of nanometers. We unambiguously establish that 1T -CrTe 2 flakes are ferromagnetic above room temperature, have an in-plane easy axis of magnetization, low coercivity, and we confirm that their Raman spectroscopy signatures are two modes, E 2g (103.5 cm −1 ) and A 1g (136.5 cm −1 ). We also prove that thermal annealing causes a phase transformation to monoclinic Cr 5 Te 8 and, to a lesser extent, to trigonal Cr 5 Te 8 . In sharp contrast with 1T -CrTe 2 , none of these compounds have a Curie temperature above room temperature, and they both have perpendicular magnetic anisotropy. Our findings reconcile the apparently conflicting reports in the literature and open opportunities for phase-engineered magnetic properties.

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Redetermination the basic cell trigonal Cr5Te8 single crystal structure and its temperature dependence Raman spectra

Cited by 7 publications

References 23 publications

Field-Free Improvement of Oxygen Evolution Reaction in Magnetic Two-Dimensional Heterostructures

Field-Free Improvement of Oxygen Evolution Reaction in Magnetic Two-Dimensional Heterostructures

Pressure-Induced Structural Phase Transition, Anomalous Insulator-to-Metal Transition, and n–p Conduction-Type Switching in Defective, NiAs-Type Cr_1−δTe

Stability of the In-Plane Room Temperature van der Waals Ferromagnet Chromium Ditelluride and Its Conversion to Chromium-Interleaved CrTe$_2$ Compounds

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Redetermination the basic cell trigonal Cr5Te8 single crystal structure and its temperature dependence Raman spectra

Cited by 7 publications

References 23 publications

Field-Free Improvement of Oxygen Evolution Reaction in Magnetic Two-Dimensional Heterostructures

Field-Free Improvement of Oxygen Evolution Reaction in Magnetic Two-Dimensional Heterostructures

Pressure-Induced Structural Phase Transition, Anomalous Insulator-to-Metal Transition, and n–p Conduction-Type Switching in Defective, NiAs-Type Cr1−δTe

Stability of the In-Plane Room Temperature van der Waals Ferromagnet Chromium Ditelluride and Its Conversion to Chromium-Interleaved CrTe$_2$ Compounds

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Pressure-Induced Structural Phase Transition, Anomalous Insulator-to-Metal Transition, and n–p Conduction-Type Switching in Defective, NiAs-Type Cr_1−δTe