Magnetization, shape memory and hysteresis behavior of single and polycrystalline FeNiCoTi

H. Sehitoglu, C. Efstathiou, H. J. Maier, Y. Chumlyakov

Research output: Contribution to journalArticlepeer-review


We report on the shape memory characteristics and magnetic behavior of polycrystalline and single crystalline FeNiCoTi. Predeforming the samples in the martensitic state and biasing of the martensite variants produced anisotropy in the magnetization behavior allowing the 'easy axis' to be identified as the 'a-axis' in the martensitic state. Based on these results, we provide an estimate of the magnetic anisotropy energy as 8.34×105 ergs/cm3. The results confirm the different magnetization behavior in the martensitic and austenitic states, and the shift in transformation temperatures upon application of a magnetic field. Shape memory strains near 2.5% are demonstrated under constant stress temperature cycling and upon heating at zero stress after deformation. We present a thermodynamics based theory that explains the origin of the hysteresis in this class of alloys emanating from the dissipation of energy due to plastic deformation. We predict the thermal hysteresis (135 K), and the shift in transformation temperature (14 K) with applied magnetic fields in agreement with the experimental results. The possibility of utilizing these classes of alloys as magnetic shape memory alloys is discussed.

Original languageEnglish (US)
Pages (from-to)89-99
Number of pages11
JournalJournal of Magnetism and Magnetic Materials
StatePublished - Apr 2005


  • Anisotropy
  • Energy dissipation
  • Magnetic shape memory

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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