  The detailed analysis of the problem of possible magnetic behavior of the
carbon-based structures was fulfilled to elucidate and resolve (at least
partially) some unclear issues. It was the purpose of the present paper to look
somewhat more critically into some conjectures which have been made and to the
peculiar and contradictory experimental results in this rather indistinct and
disputable field. Firstly the basic physics of magnetism was briefly addressed.
Then a few basic questions were thoroughly analyzed and critically reconsidered
to elucidate the possible relevant mechanism (if any) which may be responsible
for observed peculiarities of the "magnetic" behavior in these systems. The
arguments supporting the existence of the intrinsic magnetism in carbon-based
materials, including pure graphene were analyzed critically. It was concluded
that recently published works have shown clearly that the results of the
previous studies, where the "ferromagnetism" was detected in pure graphene,
were incorrect. Rather, graphene is strongly diamagnetic, similar to graphite.
Thus the possible traces of a quasi-magnetic behavior which some authors
observed in their samples may be attributed rather to induced magnetism due to
the impurities, defects, etc. On the basis of the present analysis the
conclusion was made that the thorough and detailed experimental studies of
these problems only may shed light on the very complicated problem of the
magnetism of carbon-based materials. Lastly the peculiarities of the magnetic
behavior of some related materials and the trends for future developments were
mentioned.
