Room temperature magnetic refrigerator using both metal Gd or/and Gd-Si-Ge alloys and a permanent magnetic field source

Publisher Summary This chapter introduces a room temperature magnetic refrigerator using both metal Gd or/and Gd-Si-Ge alloys and permanent magnetic field source. The permanent magnet is assembled in a shape of cylinder in which there are 1.4 Tesla uniform magnetic fields. A temperature span of 25 K is reached for the alloys when environment temperature is about 290 K. In real circulation, the system reaches a temperature span more than 26 K when Gd spheres are used, and a temperature span of 25 K when Gd 5 Si 1.985 Ge 1.985 Ga 0.03 spheres are used. When these two kinds of working materials are substituted with Gd 5 Si 2 Ge 2 alloy, the temperature span is less than 20 K. But if the alloys are short of Ga, the less temperature range could be reached at the same temperature. In addition, the magnetic refrigerator is also filled with metal Gd as the refrigerant; a temperature span of 26 K is reached. Although it cannot be concluded that Gd-Si-Ge alloys have a better cooling effect than metal Gd, but the alloys are indeed valuable because of its optimal chemical stableness.