You can detect a twin in a crystal by TEM and the twin does not need to be necessarily parallel to the beam direction - twins typically produce quite specific diffraction contrast, so you can easily identify them. Of course if you want to have a high resolution of a twin plane you will have to prepare a sample perpendicular to the twin and parallel to the zone axis.

There is an awful lot what you can learn about a crystal in TEM, there are tons of books about it, my favourite being Electron Microscopy of Thin Crystals by P.Hirsch - it's a bible of the topic.

If you have a specific question - do not hesitate to ask, but just the list of what is possible to do with TEM may easily take tens of pages.

Choice of the sample preparation method typically depends on what you want to study. If you are interested in a particular place on the sample with a micron precision, than FIB is your only choice.

Powders below half a micron in size are easy to prepare - you simply sonicate them in ethanol and dropcast on holey film.

Ultratome is good for plastics and soft materials, though it's application for hard materials and crystals is exotic and may be expensive (you will need a diamond knife, which will break often).

Electrochemical polishing is sometimes the only choice for metals, if you want to avoid introducing artifacts by mechanical processing.

There is a classical bulk sample prep route, which includes cutting, polishing, dimpling and ion polishing. In this way you can achieve large transparent areas for diffraction contrast imaging and statistical analysis. The method requires quite some expertise and hands on experience, you cannot expect getting good samples the next month you started to learn it.

There is a vast variety of other more special approaches, not mentioning methods specific for different branches of microscopy, like biology for example.

You can detect a twin in a crystal by TEM and the twin does not need to be necessarily parallel to the beam direction - twins typically produce quite specific diffraction contrast, so you can easily identify them. Of course if you want to have a high resolution of a twin plane you will have to prepare a sample perpendicular to the twin and parallel to the zone axis.

There is an awful lot what you can learn about a crystal in TEM, there are tons of books about it, my favourite being Electron Microscopy of Thin Crystals by P.Hirsch - it's a bible of the topic.

If you have a specific question - do not hesitate to ask, but just the list of what is possible to do with TEM may easily take tens of pages.

Choice of the sample preparation method typically depends on what you want to study. If you are interested in a particular place on the sample with a micron precision, than FIB is your only choice.

Powders below half a micron in size are easy to prepare - you simply sonicate them in ethanol and dropcast on holey film.

Ultratome is good for plastics and soft materials, though it's application for hard materials and crystals is exotic and may be expensive (you will need a diamond knife, which will break often).

Electrochemical polishing is sometimes the only choice for metals, if you want to avoid introducing artifacts by mechanical processing.

There is a classical bulk sample prep route, which includes cutting, polishing, dimpling and ion polishing. In this way you can achieve large transparent areas for diffraction contrast imaging and statistical analysis. The method requires quite some expertise and hands on experience, you cannot expect getting good samples the next month you started to learn it.

There is a vast variety of other more special approaches, not mentioning methods specific for different branches of microscopy, like biology for example.

Respected Andrey Chuvilin,

Thanks for your kind mail. I want to know whether my organic material having twinning property or not. Is it possible to characterize by using the grained powder of the crystalline material dispersed in the standard solvent or what size of single crystal is need to study.

Can you say what is your material and what is the size of the primary crystals?

My material is methylpyridinium 4-nitrophenolate 4-nitrophenol. Primary Crystal is having .05mm thickness and 0.5mm length.

For your kind information : I absorbed twinning on the 111 surface. By selective seeding i can avoid twinning on the surface. But most of the spontaneous nucleated crystal get started twinning after attaining few mm thickness (But not observe in initial stage)

It is not so simple to identify twins.

In general, you should have diffraction patterns along two directions (orthogonal if we consider cubic lattices). Then: you will distinguish the host and the twinned lattices along the tilt axis; along other directions you may have: i) perfectly coincided lattices (but you may have systematically situated reflections with higher intensity) or ii)you will observe two different lattices. Then you have to determine the CSL (or another way of description of the twins?)

>>My material is methylpyridinium 4-nitrophenolate 4-nitrophenol.

Forget about TEM - there is no way you can make a sample from such a crystal in a simple way, and there is no simple way to observe it in TEM.

I would suggest you try single crystal XRD (if you have access to a tool with 2 axis goniometer).

The other trivial approach would be to try etching - if you know a solvent which would preferentially dissolve particular crystallographic plane (which most of them usually do) - than you have a chance to see twins in the etch figures simply in the optical microscope.

Such results have been published (e.g. M. Wrobel et al., Scripta Metallurgica, 32 (1995) 1985, Scripta Metallurgica, 35 (1996) 417, Materials Chemistry and Physics, 81 (2003) 524, S. Dymek and M. Wrobel, Materials Chemistry and Physics, 81 (2003) 552

You might also be interested in papers

M. Blicharski et al., "Inhomogeneities of Microstructure Evolved in Metals under Plastic Deformation", Journal of Materials Processing Technology, 53 (1995) 75, S. Gorczyca et al. "Nomenclature for Structural Heterogeneities Produced by the Deformation of Metals", Archives of Metallurgy 31 (1986) 23

Data indicated by me apply to metals, not to chemicals, sorry