Influence of Ge and Bi substitution on the magnetic and magnetocaloric properties of LaFe11.4Si1.6

KOLAT V. S., KAYA A., İZGİ T., GENÇER H., BAYRİ N., ATALAY S.

JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, cilt.12, sa.5, ss.1129-1134, 2010 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 12 Sayı: 5
  • Basım Tarihi: 2010
  • Dergi Adı: JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.1129-1134
  • İnönü Üniversitesi Adresli: Evet

Özet

In this work, the magnetic and magnetocaloric properties of LaFe11.4S1.6-xGex (x = 0.05, 0.1 and 0.2) and La1-xBixFe11.4Si1.6 (x = 0, 0.1 and 0.2) compounds have been investigated. X-ray results indicate that the samples with lower Ge and Bi contents mainly consist of the NaZn13-type phase with a small amount of alpha-Fe impurity phase. The alpha-Fe impurity phase increases with increasing concentrations of Ge and Bi. The Curie temperature of the samples also increases slightly with increasing Ge and Bi contents. The spin-wave dispersion coefficient D, exchange constant J and average mean-square range of exchange interaction ()(1/2) have been calculated. The increase in Curie temperature is attributed to an increase in the average Fe-Fe distance and ferromagnetic interactions. The peak values of the magnetic entropy change vertical bar Delta S-m vertical bar are found to decrease with increasing Ge and Si contents. This is attributed to a change of the phase transition from first order to second order. The peak values of vertical bar Delta S-m vertical bar are 22.38 J/kg K for LaFe11.4Si1.6, 12.58 J/kg K for LaFe11.4Si1.5Ge0.1 and 14.25 J/kg K for La0.9Bi0.1Fe11.4Si1.6 at a magnetic field of 6 T.