A generalized magnetic refrigeration scheme

Abstract

We have investigated the magnetocaloric effects in antiferromagnets and compared them with those in ferromagnets using Monte Carlo simulations. In antiferromagnets, the magnetic entropy reaches a maximum value at a finite magnetic field when the temperature is fixed below the Néel temperature. Using the fact, we proposed a protocol for applying magnetic fields to achieve the maximum efficiency for magnetic refrigeration in antiferromagnets. In particular, we found that at low temperatures, antiferromagnets are more useful for magnetic refrigeration than ferromagnets.

Modeling specific heat and entropy change in La(Fe–Mn–Si)13–H compounds

“…Magnetic entropy is then derived from the density of states through common thermodynamic relations. In particular, Tamura et al [19] have recently applied this approach to the Ising ferromagnet, deriving the density of states by means of the fast Wang-Landau sampling algorithm [20]. The resulting model allows to better capture the peculiar shape of the specific heat peak observed at the first order phase transition of the La(Fe-Mn-Si) 13 -H 1.65 compounds and it is promising for the eventual inclusion of magnetoelastic effects.…”

Magnetic ordered structure dependence of magnetic refrigeration efficiency

“…We show that the protocol proposed in Ref. 80 is useful for obtaining high magnetic refrigeration efficiencies in the two typical processes.…”

“…80, the magnetic refrigeration efficiency is only considered with respect to the amount of heat absorption during the isothermal demagnetization process. In this work, we examine the magnetic refrigeration efficiency in the isothermal demagnetization and adiabatic magnetization processes.…”

“…80 and aims to elucidate the relation between the magnetic refrigeration efficiency and typical magnetic ordered structures. In particular, we focus on the following.…”

“…In Ref. 80, we focused on just the isothermal demagnetization process and investigated DS M of the Ising model on a simple cubic lattice using the Wang-Landau method. [81][82][83] Reference 80 studied DS M in a ferromagnet and in A-, C-, and G-type antiferromagnets, which are typical magnetic ordered structures.…”