Dear Xiang Liu,

It all depends on the type of sample, namely: are the nanoparticles in the form of a powder or is this a solution of nanoparticles? In any case, to obtain qualitative sample for TEM studies, it is necessary that the concentration of magnetite particles was low. From my point of view, if You need to carry out investigations of prepared samples without previous treatment then it's looks like that there is only one simple possibility to obtain sample with isolated particles, namely: to dilute freshly prepared sample of magnetite in the solvent which was used for NPs preparation, and after that to subject the sample to ultrasonic treatment. The drop of resulting solution (magnetite + solvent) should be placed on the grid used for TEM and rapidly dried. From the other hand, if You have carbon-coated grid, You can immerse it into the magnetite solution. The second way is more preferred and allows to dry the sample thoroughly and quickly before viewing.

I hope this will be helpful)

With kind regards,

Liliya.

Dear Xiang Liu,

It all depends on the type of sample, namely: are the nanoparticles in the form of a powder or is this a solution of nanoparticles? In any case, to obtain qualitative sample for TEM studies, it is necessary that the concentration of magnetite particles was low. From my point of view, if You need to carry out investigations of prepared samples without previous treatment then it's looks like that there is only one simple possibility to obtain sample with isolated particles, namely: to dilute freshly prepared sample of magnetite in the solvent which was used for NPs preparation, and after that to subject the sample to ultrasonic treatment. The drop of resulting solution (magnetite + solvent) should be placed on the grid used for TEM and rapidly dried. From the other hand, if You have carbon-coated grid, You can immerse it into the magnetite solution. The second way is more preferred and allows to dry the sample thoroughly and quickly before viewing.

I hope this will be helpful)

With kind regards,

Liliya.

Liliya Bazylyak Thank you Prof.

Hello Dr. Liu,

You can try ultrasonic bath or probe method. You need a solution of the nanoparticles, perform the ultrasonication, then oven dry. In terms of solvents, you may have a read at--

Article Solubilization, dispersion and stabilization of magnetic nan...

Thanks

In suspension the long range attractive magnetic forces will always overcome a short range charge stabilization mechanism. Thus agglomeration and aggregation will follow exactly as night follows day and day follows night. Van der Waals forces are always attractive too. You need steric stabilization in the system e.g. a 50 kDa PEG or PEI adsorbed on the surface. This will at least prevent the magnetite particles getting closer enough to combine and form a cluster. The density is such that it does not require much agglomeration for the particles to start settling.

Or create your magnetite on a (inert?) carrier similar to metallic catalysts. This will create small particles

For SAED you need to prepare a lot of sample, I needed two days to adequately perform TEM for my iron based nanoparticles.

If you prepared in solution you can't do much than drop on copper grid and dry. Manganese also change crystal structure when in solid comparing to liquid.

From my point of view, if You need to carry out investigations of prepared samples without previous treatment then it's looks like that there is only one simple possibility to obtain sample with isolated particles, namely: to dilute freshly prepared sample of magnetite in the solvent which was used for NPs preparation, and after that to subject the sample to ultrasonic treatment. The drop of resulting solution (magnetite + solvent) should be placed on the grid used for TEM and rapidly dried. From the other hand, if You have carbon-coated grid, You can immerse it into the magnetite solution.

In other hand, in suspension the long range attractive magnetic forces will always overcome a short range charge stabilization mechanism. Thus agglomeration and aggregation will follow exactly as night follows day and day follows night. Van der Waals forces are always attractive too. You need steric stabilization in the system e.g. a 50 kDa PEG or PEI adsorbed on the surface. This will at least prevent the magnetite particles getting closer enough to combine and form a cluster. The density is such that it does not require much agglomeration for the particles to start settling.

Please check below attachment link..

Article Solubilization, dispersion and stabilization of magnetic nan...

Thanks for your question@Xiang Liu

Yedluri Anil Kumar Excellent copy and paste of my answer....

@alan but can that be done with Manganites?

Stefan Ručman

The general stability thesis I quoted can be applied to all magnetic (and non-magnetic) systems.