When characterized with XRD , my prepared sample show peaks which are broader(bottom) than crystalline peaks but unlike amorphous materials, have sharp top. Is there any limit of intensity or full width half maxima (FWHM) value which differentiates crystalline peaks form amorphous peaks.
Crystalline solids will give sharp X-ray diffraction peak, while a complete amorphous material should not give any X-ray peaks or maybe a very wide peaks for a high intensity peak angles. amorphous materials made from small Nanoparticles hardly have a crystalline form formation. For more information see the following link:
power point, “Solid Surface and Nanoscale materials Structure” July 2016 DOI: 10.13140/RG.2.2.31947.59684 Conference: Charmo At: University of Charmo Affiliation: University of Salahaddin
Your question needs a clear definition of the various states of matter.
As amorphous material people usually think of something like a glass or liquid. The material is considered homogeneous and void of long range structural order. The lack of long range order can be static, as in the case of glasses or (in addition) dynamic, as in the case of liquids.
A crystalline material has long range periodic order. The quality of the long range order may vary, please look up terms like mosaicity.
Crystalline solids may partially lack long range order. As example think of layered materials with stacking faults. Within the (individual) layers, long range order usually exists over many unit cells. Along the normal to the layers, the periodic long range order is broken.
Independent of these tow terms (no-long range order / long range order) you have to look at the finite size of an object.
Most nanoparticles will have good internal order but the order is limited to the size of the nanoparticles. Thus one usually does not refer to nanoparticles as to be in an amorphous state. Things get to be messy, if the order within the nanoparticle is disturbed, for example due to different atomic radii in an intermetallic alloy or due to surface distortions. In my experience even distorted alloys are closer to a crystalline order than to a true glass like state.
A truly amorphous material will have a smooth diffraction pattern. All pattern I've seen so far exhibit just one maximum, possibly a weaker shoulder in the case of molecular liquids.
The diffraction pattern of a (crystalline) nanoparticle will depend on: size, shape, distortions, defects etc and can take up anything from the regular powder diffraction pattern of a well ordered crystalline solid to a pattern with hardly any sharp features. All pattern that I have seen will, however, have more than just one maximum.
Unfortunately your data lack the quality to make a definite statement. You need to collect the data again overnight with good intensity statistics. This will give you the answer that you are looking for.
There seem to be at least three maxima, the main at roughly 18° 2Theta, the smaller apparently sharper one at 24°2Theta and the very broad and weak one at 42°. As the data stand this last maximum might be there or not, the noise level is inacceptably high. Take the data again with at least 8 time the exposure time.
With the noise, it still looks like a nanoparticle type sample, it might have anisotropic shape, a hefty amount of distortions, as peaks above 40° are all either absent of super broad.
Amorphous solids have irregular surfaces, thereby do not give well-resolved x-ray diffraction peaks as opposed to crystalline solids with well defined diffraction patterns.
Vaishali Paul , please be aware that an irregular surface that a glass may show is caused by the interior non-periodic arrangement of the atoms. In contrast, the periodic order within a crystal (which makes nice flat internal lattice planes) is reflected by the ability of single crystals to show nice flat surfaces. In both cases it is the internal arrangement of the atoms, which is responsible for the surface and in turn is responsible for the diffraction pattern.
It is wrong to argue the other way around. The shape and details of a surface of a solid do not always reflect the internal structure. The diffraction pattern will be determined by the surface structure, as the diffraction pattern is a bulk property of the complete crystallite/particle. A distorted surface of a tiny nanoparticle will affect the diffraction pattern as well, but only since the volume of atoms close to the surface is a very appreciable fraction of the total volume.
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