Investigation of the Heusler materials for the magnetocaloric refrigeration and direct magnetocaloric measurement set-up

Introduction

Current cooling technology: Gas-compression based Problem with gas compression technology
• Toxic gases are used (environmental issue)
• Huge energy consumption
• Compressor cost is very high
• No scope to increase efficiency

New technology is necessary: Magnetocaloric effect (MCE) based cooling emerged as the best alternative for gas-compression based technology.

Objectives

To prepare low hysteresis Heusler alloys and investigate them for application in magnetic refrigeration (cooling).

Design of the insert for direct measurement set-up

Conclusion

• Sample Ni1.9Pt0.1Mn1.4In0.6 was prepared by standard arc melter set up.
• To determine the transition temperature and Hysteresis we performed the Iso-field protocol measurement.
• Magnetization measurement was done by three protocols:
Second order protocol measurement
Loop protocol measurement
Iso-field protocol measurement
• We calculated the change in entropy with help of Maxwell’s relation at different fields by above three protocols (at 3 Tesla shown here).
• We found approximately same value of ΔS in each case.
• With the help of above analysis we can say that Ni1.9Pt0.1Mn1.4In0.6 can show reversible MCE and It can be used as caloric material in magnetic cooling device.
• We will be able to estimate the adiabatic temperature change directly from the above designed experimental setup.