Recently, I have prepared a hydroxide sample, which could be attracted by magnet. But, the temperature dependent magnetization measurement shows that the sample is paramagnetic in the whole range of temperature from 4 K up to room temperature. I want to know the reason why this could be happen and is there any other materials show similar phenomenon as my hydroxide sample? I am looking forward for your advice. Thank you. --- Long Yuan, From Jilin University
Not only ferromagnetic materials are attracted by magnets, so are paramagnetic ones ! Most salts of transition metals fall in this category, so your observation is quite normal ! What is the metal ? As soon as you have un-paired electrons, the resultant compound is paramagnetic, and hence attracted by magnets. The more un-paired electrons you have, the higher is the attraction.
Alain
How could I calculate the amount of un-paired electrons in the samples? The metals are Dy and Al. This coumpound has a similar structure as that composed of Dy and Fe. However, the last one could not be attracted by the magnets, which is also paramagnetic according to the temperature dependent magnetization measurement. What makes the difference by just replacing Al by Fe?
Thank you, Alain.
Dear Long Yuan,
(i) how exactly do you determine the attraction by a magnet? It might be good to find someone doing a real measurement of paramagnetic susceptibility of your compound.
(ii) the paramagnetic behavior in the Dy-Al-compound almost certainly derives from the very large atomic moment in the 4f shell of the Dy atoms.
(iii) there is indeed a difference between Al and Fe. Whereas I hold it pretty unlikely that Al atoms build up a magnetic moment, chances are much higher that Fe atoms do. Also, combinations of 3d and 4f elements frequently involve antiferromagnetic correlations between the two. Fe-Gd (as a metal) for example is a ferrimagnet. Likewise, in your paramagnetic Gd-Fe compound it could be (I am guessing!) that the interactions between Gd and Fe reduce the paramagnetic susceptibility.
(iv) To understand this better, it would be important to measure the susceptibilities of both substances quantitatively and to determine the Curie constant. This should give an idea about the effective paramagnetic moment and hence the nature of the magnetic response.
Dear Mr. Long Yuan,
the name of a material is secondarly. I think for this effect is a analysis interesting, if the
material have "free" 3D electron behavoir. And the condition for this 3D free electron condition for a spin moment.
I think a ESR analysis is good for some answers.
Yours Sincerely
F. Gräbner
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