  Nanosheets of nickel with thickness equal to 0.6 nm have been grown within
the interlayer spaces of Na-4 mica. The sheets are made up of percolative
clusters of nanodisks. Magnetization characteristics indicate a
superparamagnetic behavior with a blocking temperature of 428 K.The magnetic
anisotropy constant as extracted from the coercivity data has been found to be
higher than that of bulk nickel by two orders of magnitude. This is ascribed to
a large aspect ratio of the nickel nanophase. The Bloch exponent is also found
to be considerably different from that of bulk nickel because of a size effect.
The Bloch Equation is still found to be valid for the two dimensional
structures.
