| Popis: |
Recent discovery of Hf-Cu base bulk metallic glasses [1] increased the interest in amorphous alloys consisting of the early and late transition metals. Here, we report new results for the magnetic properties of Hf100-xFex metallic glasses in the concentration range (20 ≤ x ≤ 43) below the onset of long range ferromagnetic order, xc ≈ 50 [2]. We have measured magnetization and ac susceptibility of Hf100-xFex (x = 20, 25, 40 and 43) glassy alloys in the temperature range 1.5K to 300K and magnetic field up to 5.5T. The magnetic susceptibility χ exp increases rapidly with x, which is due to presence of Fe 3d states at EF and the onset of magnetic correlations in the vicinity of transition into the ferromagnetic state, xc ≈ 50. The onset of correlations shows up in the Curie-Weiss term in χ exp for x = 25 and superparamagnetism for x = 40 and 43 (with blocking temperatures rapidly increasing with x). Thus, the formation of magnetic clusters inside the paramagnetic matrix precedes the formation of ferromagnetic state in Hf-Fe metallic glasses [3]. The results are compared with those for similar Zr-base glassy alloys. [1] A.Inoue, W.Zhang, T.Zhang and K.Kurosaka, Acta Materialia, 49 (2001) 2645 ; [2] S.H. Liou, G.Xiao, J.N. Taylor and C.L. Chien, Journal of Applied Physics, 57 (1985) 3535 ; [3] D. Pajić, K. Zadro, R. Ristić, I. Živković, Ž. Skoko and E. Babić, Journal of Physics: Condensed Matter, 19 (2007) 296207. |
