what are the common uses of fermium?

Answer 1

None,

Fermium (Fm and atomic number 100) is an artificial element that has been made in only small quantities by bombarding plutonium. We don't even know all of it's chemical properties.

According to Wikipedia: http://en.wikipedia.org/wiki/Fermium
"Only small amounts of fermium have ever been produced or isolated. Thus relatively little is known about its chemical properties. Only the (III) oxidation state of the element appears to exist in aqueous solution. 254Fm and heavier isotopes can be synthesized by intense neutron bombardment of lighter elements (especially uranium and plutonium). During this, successive neutron captures mixed with beta decays build the fermium isotope. The intense neutron bombardment conditions needed to create fermium exist in thermonuclear explosions and can be replicated in the laboratory (such as in the High Flux Isotope Reactor at Oak Ridge National Laboratory). The synthesis of element 102 (nobelium) was confirmed when 250Fm was chemically identified. There are no known uses of fermium outside of basic research. Fermium is the eighth transuranic element."

Answer 2

Fermium Uses

Answer 3

Research is the only practical use that I have heard of.