MLZ Conference: Neutrons for Energy

Study of magnetocaloric materials in the system Mn$_{2-x}$M$_x$Sb (M=Fe, Co)

19 Jul 2016, 16:50

2h 40m

Hotel Wyndham Grand Axelmannstein, Bad Reichenhall, Germany

Board: 5

Poster Energy storage & transformation Poster Session

Speaker

Mr Mamuka Chikovani (Jülich Centre for Neutron Science/Peter Grünberg Institut-4, Forschungszentrum Jülich GmbH, Germany)

Description

Magnetocaloric refrigeration is an emerging technology in today's cooling devices and it has a potential to save about 20-30 % of energy compared to conventional vapor compression technology. Nowadays, the most important issue is to find cheap and abundant materials exhibiting a sizable magnetocaloric effect. We report on preparation and characterization of compounds of general composition Mn2-xMxSb system with M = (Fe, Co). The substitution on the Mn site has an effect on magnetic properties and magnetic transitions. We synthesized samples of different stoichiometry by inductive melting of the elements in a cold crucible and performed studies using x-ray powder diffraction method and macroscopic magnetization measurements. Based on these data we could then calculate the entropy change. In the Fe-containing samples, in particular in Mn1.8Fe0.2Sb, we observe a small MCE associated to a paramagentic-ferrimagnetic phase transition. The Co-doped samples reveal a more sizable MCE accompanying a ferri-to-antiferromagnetic phase transition. Currently we study the response of the lattice parameter to the magnetic transitions with low temperature powder diffraction (300-15 K).