Magnets are used in everyday life, but fundamental mechanisms of magnet (being magnetic) require understanding of quantum mechanics. In general materials with localized magnetic moment are supposed to be magnetically ordered below a certain transition temperature. However it has been found that many correlated systems with well-defined local moment do not show any signature of magnetic ordering down to lowest temperature (that can be achieved in laboratory). It turns out that underlying crystal structures where the local moments reside play a crucial role in determining magnetic ordering tendency. In some exotic materials called spin liquid, spins behave like fermi liquid while charge excitation is gapped, generating spin-charge separation of electrons (for more details; see our papers on arXiv.org).