DCMPMS Seminars

Magnetostructural coupling and giant-magnetocaloric effect in Mn-Co-Ge compound

by Dr. Santosh Kumar Pal (Department of Physics, Institute for Energy Technology - IFE, Kjeller, Norway)

Tuesday, July 17, 2018 from to (Asia/Kolkata)
at AG80
Description
Magnetic cooling employing magnetocaloric effect is a rapidly growing technology with a potential of becoming more economical, energy efficient and environmental friendly cooling technology. The magnetocaloric effect of a material can be significantly improved by coupling the magnetic spin and structural(lattice vibration) degrees of freedom. This talk is focused on establishingmagnetostructural coupling via tuning the magnetic and structural transition temperatures of Mn-Co-Ge compound by means of chemical pressure induced by elemental substitution. The coupling leads to a first-order magnetostructural phase transition which results in a giant magnetocaloric effect. Substitution of Mn by Cu in MnCoGe has resulted in thefirst-order phase transition in a wide temperature window of 100 K. This results in a maximum entropy change of -58 J.kg-1.K-1near room temperature for a magnetic field change of 5 T for 11 at.% of Mn substitution. Additionally, the Mn1-xCuxCoGe compounds exhibit magnetic field induced magnetostructural transformations. These findings reveal that with a giant magnetocaloric effect in a wide temperature range, this class of materials can be of significant importance for the development of green and efficient solid-state-magnetic cooling devices.