Magnet
A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include the elements iron, nickel and cobalt, some alloys of rare-earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a magnetic field, by one of several other types of magnetism.
Plastic magnet
In February 2002, researchers from Ohio State University & University of Utah developed the world's first light-tunable plastic magnet.
The plastic material became 1.5 times more magnetic when blue light shines on it. Green laser light reversed the effect somewhat, by decreasing the material's magnetism to 60 percent of its normal level. The plastic magnet was made from a polymer made of tetracyanoethylene (TCNE) combined with manganese (Mn) ions -- atoms of the metal manganese with electrons removed. The magnet functioned up to a temperature of 75 K (about -200ºC, or -325ºF).