Diamagnetism

In a diamagnetic material, the external field induces a magnetisation opposite to the field (negative susceptibility).
In a non-uniform field, such a material is repelled by the stronger part of the field.
So a diamagnetic material moves from the stronger to the weaker parts of the field. (Paramagnetic and ferromagnetic materials move from weaker to stronger parts.)
Example: a diamagnetic liquid in a U-tube between magnet poles shows a fall in level in the arm placed in the strong field.