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magnetic entropy change of 5.9 Jkg 1 K 1 and an adiabatic temperature change of
2 K (from 0 to 1.2 T). However, the MCE decreases with increasing x value.
Therefore, the LCSM compound (x = 0.055) with a Curie temperature of 285 K
(which is relevant for near-room-temperature magnetic applications) has a magnetic
entropy change of 2.8 Jkg 1 K 1 and an adiabatic temperature change of 1 K for a
magnetic
eld change from 0 to 1.2 T. In spite of the LCSMs having a rather low
MCE, they are still a promising group of MCMs that could be used in magnetic
refrigeration. This is mostly due to their low price, good corrosion resistance, the
easy tunability of the T C and the ease of processing [ 30 ].
2.2.5 Layered MCMs
As stated in Sect. 2.1 (General criteria for the selection of the MCM), one of the
important characteristics of MCMs is to have a large MCE over as wide a tem-
perature range as possible, since the AMR should operate with a large temperature
span. Since the MCMs exhibit their largest MCE around their Curie temperature,
the idea has been developed to build the AMR from different MCMs along the
regenerator. Each material should have its Curie temperature (and therefore the
largest MCE) in a different temperature range. In this way, the AMR could have a
signi
cant MCE across its full operating temperature span. As was presented in the
previous sections on different MCMs, the tuning of Curie temperatures is of course
possible by changing the concentrations of the certain elements in magnetocaloric
compounds. Building the AMR from several MCMs with different Curie temper-
atures will lead to a step-wise change in the Curie temperatures along the AMR
'
s
length (Fig. 2.2 a).
Fig. 2.2 a A schematic diagram of a step-wise T C ; b Linearly continuously T C layered AMR
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