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Multi-Calorics

(Multi)Caloric materials, which undergo a reversible thermal change when an external field is applied/withdrawn, are promising candidates in energy-efficient solid-state cooling devices. They can be classified as: magnetocalorics (magnetic field), electrocalorics (electric field), elastocalorics (stress), and barocalorics (pressure). A coupling of several of these effects may increase this applications potential.

Our research mainly focuses on compounds in intermetallic systems (e.g., Mn5-xFexSi3-yGey), which exhibit the magnetocaloric effect (2-4 J/kg K) at low magnetic field ~2T, and on spin crossover compounds that have the barocaloric effect (40-80 J/kgK) at low hydrostatic pressures  (~1 GPa). The large entropy changes in these materials originate from both spin ordering and lattice vibrations that are strongly coupled.

The overall objective of our research is to understand the underlying mechanisms of the caloric effects, the interaction of the lattice with magnetic and electronic degrees of freedom and its evolution with external stimuli such as chemical composition, pressure, temperature or magnetic field. We also optimize these materials to obtain large caloric effects at small driving fields.
We employ neutron and x-ray powder and single crystal diffraction and inelastic neutron scattering under different external stimuli as well as various physical property measurements. Our aim is to exploit the material properties for real life applications in refrigeration based on solid-state caloric effects.

Multifunctional MaterialThe change in temperature of caloric materials when exposed to an external stimulus, like e.g. magnetic field, can be used for cooling technologies.
Copyright: Forschungszentrum Jülich

References:

  1. F. J. Dos Santos, N. Biniskos, S. Raymond, K. Schmalzl, P. Steffens, J. Persson, S. Blügel, S. Lounis, and T. Brückel, Spin waves in the collinear antiferromagnetic phase of Mn5Si3 , Physical Review  B 103, 024407 (2021)
  2. N. Maraytta, J. Voigt, C. Salazar Mejía, K. Friese, Y. Skourski, J. Perßon, S. M. Salman, and T.  Brückel, Anisotropy of the magnetocaloric effect: Example of Mn5Ge3, Journal of Applied Physics 128, 103903 (2020)
  3. A. Eich, A.  Grzechnik, L. Caron, Y. Cheng, J. Wilden, H. Deng, V. Hutanu, M. Meven, M.  Hanfland, K. Glazyrin, P. Hering, M. G. Herrmann, M.  Ait Haddouch, and K. Friese, Magnetocaloric Mn5Si3 and MnFe4Si3 at variable pressure and temperature, Materials Research Express 6, 096118 (2019)
  4. N. Maraytta, Y. Skourski, J. Voigt, K. Friese, M. G. Herrmann, J. Persson, J. Wosnitza, S. Salman, and T. Brückel, Direct measurements of the magneto-caloric effect of MnFe4Si3 in pulsed magnetic fields, J. Alloys Comp. 805, 1161 (2019)
  5. N. Biniskos, K. Schmalzl, S. Raymond, S.  Petit, P. Steffens, J. Persson, and T. Brückel, Spin Fluctuations Drive the Inverse Magnetocaloric Effect in Mn5Si3, Physical Review Letters 120, 257205 (2018).
  6. J. Wilden, A. Hoser, M. Chikovani, J. Persson, J. Voigt, K. Friese, and A. Grzechnik, Magnetic Transitions in the Co-Modified Mn2Sb System, Inorganics 6, 113 (2018)
  7. S. Gallus, M. Ait Haddouch, M. Chikovani, J. Persson, J. Voigt, K. Friese, A. Senyshyn, and A. Grzechnik, Crystal structure and magnetism of the FexNi8-xSi3 materials, 0 ≤ x ≤ 8, Solid State Sciences 76, 57 (2018) 

Contact: 

Karen Friese

Phone:  +49 2461 61-3826 
email:k.friese@fz-juelich.de

ORCID

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Contact: 


Manuel Angst
Phone:  +49 2461 61-2479  
email: m.angst@fz-juelich.de

ORCID

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Contact: 


Jörg Voigt
Phone:  +49 2461 61-6020  
email: j.voigt@fz-juelich.de

ORCID

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