Excellent Character of Multi-layer Type Magnetic Regenerator near 4.2 K

We investigated multi-layer type magnetic regenerators composed of several kinds of rare earth compounds with different T C in the range below 15 K. It was verified that a triple layer type magnetic regenerator was superior to the double layer types of Er0.9Yb0.1Ni and Er3Co, and Er3Ni whose characters were partially reported in CEC of 1993. We first discuss why we selected the multi-layer type, and then report the results obtained from experiment with the GM refrigerator which verified the excellent regenerative characters of the triple layer type magnetic regenerator. Large refrigeration power of ~ 1.11 watts at 4.2 K was obtained. Finally, we discuss briefly the potential of the triple layer type regenerator.