Our daily need to cooling system is grown up. The used cooling systems are the source of the harmful changes in
the global climate. And so, we need to search a new alternate cooling systems applying environmentally friendly
technology that may help in decreasing the pollutions in our world. The progress in materials science allows to
use some materials for cooling purposes. This new class of materials is so called "magnetic refrigerator". The
basics of magnetic refrigeration depends on the magneto-caloric properties to reach low temperatures and obtain
cooling system. The advantage of magnetic refrigerator (MR); First, the cooling efficiency is higher than
conventional vapor refrigerator CVM where its cooling efficiency ~30-60% while the cooling efficiency in CVM ~ 5-
10%. Second, MR can be more compactly built. Third, it is safe and an environmentally friendly cooling. In this
work, we will highlight on the scientific efforts to find optimum properties to be applied as the magnetic
refrigeration. In this review the highlights of the scientific efforts to seek for the best alternative materials to be
used as a magnetic refrigeration applications. The low coast and small size of magnetic cooling is one the
important advantage. This review consists of five sections; I. Introduction, II.Synthesis of MC materials, III. Crystal
structure of MC materials and IV. Characterization and applications of MC materials, and V. Conclusions
