Ferromagnetism in intermetallic Hf6Co23 alloy

Ferromagnetism in Hf6Co23 intermetallic alloy at room temperature has been confirmed from perturbed angular correlation measurements using 181Hf probe. The strength of hyperfine magnetic field at room temperature for this intermetallic compound has been found to be Bhf=2.5(2) T while the earlier report of hyperfine magnetic field in Hf6Co23 has discrepancy. The hyperfine magnetic field at Ta impurity site has also been calculated by density functional theory and the result is found to be Bhf=-4.964 T (at 0 K). This value is closer to the present experimental value measured at 298 K. The compound Hf6Co23 has been found to decompose reversibly to Hf2Co7 at 473 K. Ferromagnetism in this material has been found up to 423 K and its Curie temperature is, therefore, set as TC>423 K. From recent measurements by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, electron probe microanalysis and differential scanning calorimetry, Hf6Co23 was reported to be stable in a wide range of temperature and there was no phase existence of Hf2Co7 while the previous reported phase diagram showed a decomposition of Hf6Co23 to Hf2Co7 at a higher temperature. © 2021 Elsevier B.V