| Two kinds of room temperature refrigerant materials were studied in detail and their process, structure and the change of magnetic entropy were researched. The use of the magnetic refrigerant materials in practice was discussed and bi-cycle reciprocating magnetic refrigerator was designed at the same time.The atom of which number of valence electron is half of the sub-layer of electron has magnetic entropy value according to the theoretic calculation. The configuration of valence electron of Eu, Fe and Mn is 4f5d 6s , 3d64s2, 3d54s2, their number of valence electron is half or nearly half of numbers of the whole layer, consider susceptibility, heat capacity synthetically, we decide that the alloy of the three metal would have big value of magnetic entropy. The first thing to do is prepare EuFe alloy samples and measure their Tc. It is difficult to prepare EuFe by Arc Melting for the little difference between the bolting point of Eu which is 1596癈 and the melting point of Fe which is 1538癈. We can get it by mechanical alloying then sintering by SPS.The change of magnetic entropy (ASm)is the main parameter evaluating the quality of magnetic refrigerant materials and it can not be gotten by direct way now. The indirect method is taken to measure it and the first step of which is getting the magnetizing curve under different temperature, next fit of the getting data to function M(H, T), at last the needed result can be calculated through M(H, T). It is a excellent method for the whole analysis can be executed by this way.The biggest ASm of EuFe sample sintering by SPS is 1.6913/Kg ?K under IT magnetic field and which of melting sample GdSiGe is 1.9J/Kg -K under same condition of measurement with EuFe. Though ASm of EuFe is 0. 199 J/Kg ?K less than that of GdSiGe, it can be higher than now if more reasonable process is taken, EuFe can become magnetic refrigerant materials in practice some day.
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