Importance of local structural distortions in magnetocaloric effect in Mn based antiperovskites

Priolkar K. R., Dias E. T., Aquilanti G., ÇAKIR Ö., Acet M., Nigam A. K.

16th International Conference on X-ray Absorption Fine Structure (XAFS), Karlsruhe, Almanya, 23 - 28 Ağustos 2015, cilt.712 identifier identifier

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Cilt numarası: 712
  • Doi Numarası: 10.1088/1742-6596/712/1/012117
  • Basıldığı Şehir: Karlsruhe
  • Basıldığı Ülke: Almanya
  • Yıldız Teknik Üniversitesi Adresli: Evet

Özet

Mn3GaC and Mn3SnC are two antiperovskites which exhibit a large magnetocaloric effect associated with a magnetostructural transformation. Although structurally similar, the magnetic transition and the nature of magnetocaloric effect in the two compounds is completely different. While Mn3GaC transforms from a ferromagnetic to an antiferromagnetic state at T-t = 178K with the antiferromagnetic propagation vector along k - 1/2, 1/2, 1/2, in Mn3SnC the transformation occurs at Tt = 280K from a paramagnetic state to an antiferromagnetic state with k - 1/2, 1/2, 0. Mn K EXAFS has been employed to show that these differences in magnetic properties are related to local structural distortions in Mn6C octahedra which are quite different in the two compounds.