Microscopic parameters of the van der Waals CrSBr antiferromagnet from microwave absorption experiments

Microwave absorption experiments employing a phase-sensitive external resistive detection are performed for a topical van der Waals antiferromagnet CrSBr. The field dependence of two resonance modes is measured in an applied field parallel to the three principal crystallographic directions, revealing anisotropies and magnetic transitions in this material. To account for the observed results, we formulate a microscopic spin model with a bi-axial single-ion anisotropy and inter-plane exchange. Theoretical calculations give an excellent description of full magnon spectra enabling us to precisely determine microscopic interaction parameters for CrSBr.Comment: includes a supplementary information documen

Film thickness effects on morphology, optical and structural properties of chemical bath deposition grown CdS thin films for solar cell applications

CdS thin films of varying thickness were deposited on the glass substrate by chemical bath deposition (CBD) using Cadmium Chloride (CdCl2) and Thiourea ((NH2)2CS) as Cd and S sources respectively with ammonia as a complexing agent. The synthesized CdS thin films have been characterized using X-ray diffractometer (XRD), Raman spectroscopy, UV-Vis-NIR spectrophotometer, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Energy dispersion X-ray analysis (EDAX). From XRD analysis it is inferred that the obtained CdS films have highly orientated hexagonal structure with the preferential orientation along (002) plane. The optical characterization raveled that the films are highly transparent (60%–80%) in the visible region. From TEM analysis it has been observed that the inter planner spacing for CdS thin film is ∼0.31 nm and average crystallite size is 7–8 nm. The EDAX data revealed nearly stoichiometric characteristics of the CdS thin films. The SEM analysis showed that CdS thin films are smooth, homogeneous and uniform without cracks with randomly oriented spherical nanocrystallites. The CdS thin films have very high transmission in the range 600–1200 nm with the band gap >2.54 eV. The purpose of the present study is to develop window/buffer layer for CZTS solar cells

Electrical transport properties of half-heusler ScPdBi single crystals under extreme conditions

International audienc

Spatially resolved optical spectroscopy in extreme environment of low temperature, high magnetic elds and high pressure

International audienceWe present an experimental setup developed to perform optical spectroscopy experiments (Raman scattering and photoluminescence measurements) with a micrometer spatial resolution, in an extreme environment of low temperature, high magnetic eld and high pressure. This unique experimental setup, to the best of our knowledge, allows us to explore deeply the phase diagram of condensed matter systems by tuning independently these three thermodynamic parameters, while monitoring the low-energy excitations (electronic, phononic or magnetic excitations), to spatially map the Raman scattering response or to investigate objects with low dimensions. We apply this technique to bulk FePS 3 , a layered antiferromagnet with a Néel temperature of T ≈ 120 K

Microscopic parameters of the van der Waals CrSBr antiferromagnet from microwave absorption experiments

International audienc

Film thickness effects on morphology, optical and structural properties of chemical bath deposition grown CdS thin films for solar cell applications

CdS thin films of varying thickness were deposited on the glass substrate by chemical bath deposition (CBD) using Cadmium Chloride (CdCl2) and Thiourea ((NH2)2CS) as Cd and S sources respectively with ammonia as a complexing agent. The synthesized CdS thin films have been characterized using X-ray diffractometer (XRD), Raman spectroscopy, UV-Vis-NIR spectrophotometer, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Energy dispersion X-ray analysis (EDAX). From XRD analysis it is inferred that the obtained CdS films have highly orientated hexagonal structure with the preferential orientation along (002) plane. The optical characterization raveled that the films are highly transparent (60%–80%) in the visible region. From TEM analysis it has been observed that the inter planner spacing for CdS thin film is ∼0.31 nm and average crystallite size is 7–8 nm. The EDAX data revealed nearly stoichiometric characteristics of the CdS thin films. The SEM analysis showed that CdS thin films are smooth, homogeneous and uniform without cracks with randomly oriented spherical nanocrystallites. The CdS thin films have very high transmission in the range 600–1200 nm with the band gap >2.54 eV. The purpose of the present study is to develop window/buffer layer for CZTS solar cells

Synthesis of gamma-WO3 thin films by hot wire-CVD and investigation of its humidity sensing properties

In this study, monoclinic tungsten oxide (gamma-WO3) have been grown in a single step using HW-CVD method by resistively heating W filaments in a constant O-2 pressure. The formation of gamma-WO3 was confirmed using low angle-XRD and Raman spectroscopy analysis. Low angle-XRD analysis revealed that as-deposited WO3 film are highly crystalline and the crystallites have preferred orientation along the (002) direction. HRTEM analysis and SAED pattern also show the highly crystalline nature of WO3 with d spacing of similar to 0.38 nm, having an orientation along the (002) direction. Surface topography investigated by SEM analysis shows the formation of a uniform and homogeneous cauliflower like morphology throughout the substrate surface without flaws and cracks. A humidity sensing device incorporating WO3 is also fabricated, which shows a maximum humidity sensitivity factor of similar to 3954% along with a response time of similar to 14 s and a recovery time of similar to 25 s. The obtained results demonstrate that it is possible to synthesize WO3 in a single step by HW-CVD method and to fabricate a humidity sensor by using it

Wide band gap and conducting tungsten carbide (WC) thin films prepared by hot wire chemical vapor deposition (HW-CVD) method

In this letter, we report synthesis of tungsten carbide (WC) thin films having wide band gap(3.22-3.3 eV) with high electrical conductivity (80-1260 S/cm) by HW-CVD using heated using heated W filament and Tetra-fluoro-methane (CF4) gas. Formation of WC was confirmed by low angle XRD, Raman spectroscopy and x-ray photoelectron spectroscopy. UV-Visible spectroscopy analysis revealed that the synthesized films have high transmission at wavelength 500 nm. Electrical properties measured using Hall measurement show that these films are semiconductor. The obtained results imply that the growth of WC thin films is mainly from the atomic species(W and C) evaporated from the hot filament. The HW-CVD opens a novel route to synthesize wide band gap and conducting WC at a cost-efficient way for DSSCs and hydrogen evolution reaction (HER)

Synthesis of orthorhombic-molybdenum trioxide (α-MoO3) thin films by hot wire-CVD and investigations of its humidity sensing properties

In present work, we report synthesis of orthorhombic-molybdenum trioxide (α-MoO 3 ) thin films using home-build hot wire-CVD (HW-CVD) method simply by heating the Mo filament in a controlled O 2 atmosphere. The formation of α-MoO 3 was confirmed by low angle-XRD and Raman spectroscopy. Low angle-XRD analysis revealed that α-MoO 3 crystallites have orientations along (110), (101) and (111) directions while Raman spectroscopy analysis shows two prominent vibrational modes ~819 and ~994 cm -1 associated with Mo 2 -O and Mo=O respectively. SEM and TEM analysis show the formation of nano-sheets like morphology of α-MoO 3 thin films. The SAED pattern shows highly crystalline nature of α-MoO 3 . The humidity-sensing properties were investigated at room temperature by fabricating the two probe device. The humidity sensing results showed n-type behavior of α-MoO 3 . The maximum humidity sensitivity of ~6957% along with response time of ~66 s and recovery time of ~5 s were observed for α-MoO 3 thin film humidity sensor device. Our results have opened up a new avenue to grow α-MoO 3 for humidity sensor applications