X-ray tube: Cu; long fine focus; spinner stage

Pixcel 1D detector with prefix interface

X’pert highscore plus; reflectivity software; easysaxs software

1. Phase analysis of sample with flat surface of solid samples and powder samples.
2. Thin film (Grazing Incidence) XRD measurements.
3. Small Angle X-ray Scattering (SAXS)  measurements

X-rays and their generation: X-rays are high energy electromagnetic radiation with both wave and particle nature in the wavelength range of 0.01-10 nm. X-rays are produced when electrons generated from a metal cathode at high negative potential are accelerated towards a metal anode (target) at ground potential. A small percentage (< 1%) of the total loss of kinetic energy due to the impact of the electron on the metal is manifested in the form of x-rays. A spectrum of x-rays consists of continuous radiation whose wavelength is inversely proportional to applied voltage. At sufficiently high voltages, electron in the inner shell of the atom in target metal is ejected and that position is filled by other electron from outer shell associated with a release of an x-ray photon. This results in higher intensity characteristic radiation (K_α, K_β etc.) along with continuous radiation in spectrum and is specific to the target metal. The K_α characteristic radiation is specifically separated using filters from rest of the radiation and is used for diffraction.  

Diffraction: The bending of waves around the edges of an object is called diffraction. It is noticeably visible when spacing between the objects is of the same order as the incident wavelength, resulting in constructive and destructive interference. The prime reason for using x-rays in crystallography is the wavelength of x-rays being of the order of inter-planar spacing (typically ~20-30 nm) of the metals. When characteristic x-rays are incident on any metal, the electrons in the atoms of the metal oscillate about their mean position and act as new sources of electromagnetic radiation in all directions with the same frequency as of incident x-rays. This absorption and reemission of radiation is called scattering. The scattering occurs in all the planes of atoms in the metal but leads to constructive interference in specific directions resulting in diffracted beams. The intensity of the successfully diffracted beam of x-rays is extremely small compared to the incident x-rays and is captured using special detectors. The condition for successful constructive interference of x-rays is derived by Sir W. H. Bragg and his son Sir W. L. Bragg as, the path difference between diffracted beams should be an integral multiple of wave length, given by the equation:

nλ=2dsinθ

Where n- an integer indicating the order of diffraction; λ- wavelength of x-rays used; d- spacing between planes of atoms; θ- angle of incidence. The position of the peaks in the intensity of diffracted beams versus 2θ plot is material characteristic and is used for various analyses.

X-ray diffraction techniques is used in various applications like determining crystal structure, lattice parameters, phase analysis, quantitative phase composition, macro and micro strains, defect concentration, phase diagrams, and amorphicity, and to characterize polymorphs, DNA etc.

(1) Jayant K. Dewangan,a Nandita Basub and Mithun Chowdhury *a Cationic surfactant-directed structural control of NaCl crystals from evaporating sessile Droplets. https://pubs.rsc.org/en/content/articlelanding/2022/sm/d1sm01357b

(2) Kartikay, P., Sadhukhan, D., Yella, A., & Mallick, S. (2021). Enhanced charge transport in low temperature carbon-based nip perovskite solar cells with NiOx-CNT hole transport material. Solar Energy Materials and Solar Cells, 230, 111241.
https://doi.org/10.1016/j.solmat.2021.111241

(3). R. Biswas, S. Vitta, T. Dasgupta, Influence of zinc content and grain size on enhanced thermoelectric performance of optimally doped ZnSb, Mater. Res. Bull. 149 (2022) 111702. https://doi.org/10.1016/j.materresbull.2021.111702.

(4). R. Biswas, V. Srihari, S. Vitta, T. Dasgupta, Vacancy induced anomalies in the electrical transport properties of Ag-doped Zn1-xCdxSb (x=0.375) solid solutions, Appl. Phys. Lett. 120 (2022) 032102. https://doi.org/10.1063/5.0077175.

(5)Laxmi, Dinesh Kabra, Origin of Contrasting Emission Spectrum of Bromide versus Iodide Layered Perovskite Semiconductors https://doi.org/10.1021/acs.jpclett.2c00362

Please follow the sample preparation methods below, according to the nature of your analysis.

For Powder XRD

Samples should be submitted in the form of fine powder (preferably less than 10 μm) to completely fill the rectangular cavity of the sample holder of dimension of 0.6 cm3.

i.e. l = 2 cm, b = 1.5cm, h = 0.2 cm.

For Pallet Samples, the sample should have diameter of 2 cm and height 1 cm (maximum).

For Thin Film XRD and GIXRD

Sample size should be minimum 5 cm ´ 2.5 cm.

For SAXS

Details will be provided upon consultation.

 Users should fill up the XRD form and provide correct details about measurement.

• A maximum of six samples will be accepted at a time.
• Only One registration will accepted at a time.
• Maximum two samples will be accepted for half an hour sample scan.
• Collect the samples and the XRD results within 30 days of your registration.
• If user will not collect samples within 30 days then lab person will not responsible for missed samples.