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Mater Sci Nanotechnol 2017
Volume 1 Issue 3 Magnetic Materials 2017
Page 90
October 09-10, 2017 London, UK
International Conference on
Magnetostructural coupling and giant
magnetocaloric effect in MnCoGe-based
compounds
Santosh Pal
Institute for Energy Technology, Norway
S erious environmental consequences of the traditional
vapor-compression cooling techniques have turned the
research efforts towards the development of alternative
cooling techniques, and the search for materials showing
large caloric effect. Magnetic cooling technology is a rapidly
growing technology with a potential of becoming more
economical, energy efficient and environmentally friendly
cooling technology. The search of new or improving the
existing magnetic materials exhibiting large magnetocaloric
effect near room temperature but with the use of none or
negligibly small number of critical/toxic elements is a field
of intense research for magnetic cooling technology. The
magnetocaloric effect of a material can be significantly
improved by combining the lattice degree of freedom with the
magnetic one. This produces a first-order magnetostructural
transition which in turn leads to a gigantic magnetocaloric
effect. Intermetallic alloyMnCoGe is an interesting compound
which experiences amartensitic structural transformation and
a magnetic transition separated by around 100 K. Both of the
transitions can be tuned via physical and/or chemical pressure
which can lead to a magnetostructural coupling resulting
in a first-order transition and thus a giant magnetocaloric
effect. In this presentation, magnetostructural coupling and
giant magnetocaloric effect via tuning of the structural and
magnetic transitions of MnCoGe compound through partial
substitution of Co and Mn by Cu will be discussed. A giant
maximum isothermal entropy change of ~40 JKg-1 K-1 (for ∆H
= 5 T) has been obtained for 10 at %Mn substitution by Cu.
The Mn-substituted samples show a normal paramagnetic
to ferromagnetic transitions. Interestingly, in addition to
paramagnetic to ferromagnetic transitions, the Co-substituted
samples show ferromagnetic to antiferromagnetic (FM to
AFM) and then AFM to FM transitions with decreasing the
temperature. The presence of antiferromagnetic phase and
complex magnetic transitions can be possible due to the
varying Mn-Mn distances during the martensitic transition.
A comparative study of the Mn- and Co-substituted samples
and a correlation of the magnetic and structural properties
will be presented and discussed.
Materials Science and Nanotechnology