Development of a new magnetocaloric material used in a magnetic refrigeration device

Abstract

Abstract. Testing directly a magnetocaloric material in a magnetic refrigeration (MR) system is the best way to judge of its applicative potentialities. In this spirit, an oxide expected to show promising magnetocaloric properties around room temperature (Pr 0.65 Sr 0.35 MnO 3 ) was produced in large scale and shaped in order to build a regenerator. Magnetization, heat capacity, resistivity, thermal conductivity and a direct test in a MR device were carried out on this manganite. The results were compared to those observed in the reference material which is Gadolinium. The two main conclusions of these preliminary results are: (i) the Pr 0.65 Sr 0.35 MnO 3 actually displays not only a significant magnetocaloric effect but also a real refrigeration capability at room temperature; (ii) the temperature spans reached in these first experiments are even found to well compare with those obtained with Gd.

A study of the phase transition and magnetocaloric effect in multiferroic La2MnNiO6 single crystals

“…On the contrary, manganite perovskites can deal with these issues, which could compensate for their lower performance in term of the entropy and adiabatic temperature changes. 21 This family of oxides has been studied extensively in the past due to their rich variety of magnetic and electric properties. 22 More recently, numerous studies were devoted to their magnetocaloric properties showing another application for this class of materials.…”

“…23 Among all the studied magnetocaloric oxides, the La 1Àx (Ca, Sr) x MnO 3 series with x ¼ 1/3 and a ratio Mn 2þ /Mn 4þ ¼ 2 is considered actually as a reference due to their high Curie point and large magnetization. 21,23 In the mixed-valence manganites R 1Àx A x BO 3 (R ¼ lanthanide, A ¼ divalent alkaline earth and B ¼ Mn), magnetic and physical properties can be tailored easily through the control of rare earth and manganese site dopant atoms. Since the nature of the magnetic order as well as the electronic properties are governed by the super-exchange interaction in the Mn-O-Mn bond.…”

Advanced materials for magnetic cooling: Fundamentals and practical aspects

“…In comparison with La2/3(Ca, Sr)1/3MnO3, the Pr1-xSrxMnO3 compounds exhibit similar magnetocaloric properties. In addition, the limited number of constituent elements in the Pr1-xSrxMnO3 enables a better control of the magnetic properties and the synthesis process, particularly during the large scale production step (kilograms) of selected compositions 186 . In the work by Guillou et al 186 , the performance of a regenerator containing the Pr0.65Sr0.35MnO3 compound was carried out using a 0.8 T-AMR test bench.…”

“…Firstly, 0.6 kg (powder) of the selected compound was obtained through the solid state reaction. The appropriate dimensions of the desired plates (25*20*1 mm 3 ) were obtained by cutting the compacted powder (blocks) using a circular saw 186 . In order to cover the regenerator length (50 mm), the plates were stacked along the heat transfer fluid flow direction, two by two 186 .…”

“…The appropriate dimensions of the desired plates (25*20*1 mm 3 ) were obtained by cutting the compacted powder (blocks) using a circular saw 186 . In order to cover the regenerator length (50 mm), the plates were stacked along the heat transfer fluid flow direction, two by two 186 . Before its direct implementation, the physical and magnetocaloric properties of Pr0.65Sr0.35MnO3 were characterized in terms of the entropy and adiabatic temperature changes, the thermal conductivity and the electrical resistivity.…”