Lattice vibrations boost demagnetization entropy in shape memory alloy

Paul Stonaha; Mike Manley; Nick Bruno; Ibrahim Karaman; Raymundo Arroyave; Navdeep Singh; Douglas Abernathy; Songxue Chi

doi:10.1103/PhysRevB.92.140406

Lattice vibrations boost demagnetization entropy in shape memory alloy

Materials Science 2015-10-28 v4

Authors: Paul Stonaha , Mike Manley , Nick Bruno , Ibrahim Karaman , Raymundo Arroyave , Navdeep Singh , Douglas Abernathy , Songxue Chi

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Abstract

Magnetocaloric (MC) materials present an avenue for chemical-free, solid state refrigeration through cooling via adiabatic demagnetization. We have used inelastic neutron scattering to measure the lattice dynamics in the MC material Ni45Co5Mn36.6In13.4. Upon heating across the Curie Temperature (TC), the material exhibits an anomalous increase in phonon entropy of 0.22 +/- 0.04 kB/atom, which is ten times larger than expected from conventional thermal expansion. This transition is accompanied by an abrupt softening of the transverse optic phonon. We present first-principle calculations showing a strong coupling between lattice distortions and magnetic excitations.

Keywords

magnetocaloric effect phonon magnetization

Cite

@article{arxiv.1507.08933,
  title  = {Lattice vibrations boost demagnetization entropy in shape memory alloy},
  author = {Paul Stonaha and Mike Manley and Nick Bruno and Ibrahim Karaman and Raymundo Arroyave and Navdeep Singh and Douglas Abernathy and Songxue Chi},
  journal= {arXiv preprint arXiv:1507.08933},
  year   = {2015}
}

Lattice vibrations boost demagnetization entropy in shape memory alloy

Abstract

Keywords

Cite

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