Why can absorb iron magnet?
　　Why can suck iron magnets, but can not pull another metal? Why only iron, cobalt, nickel will be magnetized? Why copper and aluminum do not molecular magnets? Magnetic is a basic property of matter, all matter is magnetic media.
Divided into three types:
　　1, the paramagnetic substance that produces the same external magnetic field additional magnetic field in the magnetic field, most substances fall into this category,
　　2, anti-magnetic substance that produces the opposite with the external magnetic field additional magnetic field in the magnetic field, such as copper and inert gases.
　　3, ferromagnetic substance that produces the same strong external magnetic field additional magnetic field in the magnetic field, for example, iron, cobalt and nickel.
　　According to Ampere hypothesis first proposed, there is a permanent magnetic moment of the molecule has a certain current in paramagnetic molecules. In the absence of an external magnetic field, due to the thermal motion of molecules, the current orientation of these molecules is irregular, and therefore the magnetic field they generate on average equal to zero, the external magnetic not displayed. When an external magnetic field is present, the role of these molecules current is oriented outfield, their magnetic moment lattice steering direction of the external magnetic field, generating an external magnetic field along the direction of the additional magnetic field. That is why paramagnetic magnetization.
　　Qualitative diamagnetic molecules, in the absence of an external magnetic field, such that the structure of the molecule within their molecular currents equal to zero. When the external magnetic field is introduced, just closed a round wire to produce a magnetic field induced current is introduced, as in these anti-magnetic quality special molecules also induced current. Because the molecule is no resistance, and the same as in superconductors, the current once generated will always be endless loop until the external magnetic field caused by the withdrawal of the old reverse induced current and offset it so far.
　　Under the effect of external magnetic field, all magnetic media must be induced molecular current, that diamagnetic material is common to all, but in paramagnetic molecules, large molecules current induced magnetic moment than the current moment too narrow and more, so diamagnetic material was covered up, with only paramagnetic.