Diamagnetism is a magnetic property of some substances which makes them repelled by both poles of a magnet. Highly Oriented Pyrolytic Carbon
HOPG
has an unusually strong diamagnetic effect. HOPG can levitate over an alternated matrix of strong (N52) neodymium magnets. An alternated matrix allows for increasing the strength of the magnetic field near the magnets. In the experiment presented to the right, the surface magnetic field locally exceeds 1 Tesla.
Materials:
HOPG flake 8mm x 8mm x 0.4mm
30 Magnets N52 3mm x 3mm x 4mm
Part 2: Pencil lead
An alternative version of diamagnetic levitation is presented to the left
[reference].
An alternated matrix of N52 neodymium magnets is attached to a mild steel angle bar. Instead of HOPG, pencil lead was used. Not all pencil leads are suitable - many pencil leads contain some ferromagnetic impurities and are attracted by magnets. The most suitable leads for this presentation are 0.5mm pencil leads used for auto pencils.
Materials:
8x Magnets N52 5mm x 5mm x 5mm
3mm mild steel angle bar black 30mm x 30mm
11mm of 0.5mm pencil lead (HB Parker).
Part 3: Magnet
This magnet can levitate over a piece of HOPG, however this levitation is not caused by the diamagnetism of the HOPG. A big magnet is positioned above the small magnet to attract it, with piece of HOPG below only stabilizing the levitation (without the HOPG it is not possible to achieve stable levitation in a static magnetic field). The big magnet at the top is attached to a screw for precisely regulating the position (up/down). There is also a piece of corrugated cardboard attached to the magnet in case the balance goes wrong and the smaller magnet jerks towards the larger one, shattering on impact.
Materials:
N52 Magnet 12mm x 12mm x 12mm
N52 Magnet 5mm x 5mm x 1.4mm
HOPG plate 35mm x 20mm x 1.5mm
M5 30mm screw with nut
some Lego bricks
Addendumt
1. Levitation of a magnet between two HOPG plates.
2. Levitation of a magnet under HOPG plate.
3. Levitation of a magnet over Bismuth.
Materials:
N52 Magnet 12mm x 12mm x 12mm
N52 Magnet 5mm x 5mm x 1.4mm
2 x HOPG plate 35mm x 20mm x 1.5mm
5g Bismuth sample 12mm x 5mm
M5 30mm screw with nut
some Lego bricks
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