Affiliations: [a] National Institute of Research and Development for
Technical Physics 47 Mangeron Boulevard, R -- 6600 Iasi, Romania | [b] Institute for Materials Research, Tohoku University
2-1-1 Katahira, Aoba-Ku, Sendai 980-8577, Japan
Correspondence:
[*]
Corresponding author: Prof. Dr. Horia Chiriac, National
Institute of Research and Development for Technical Physics, 47 Mangeron Blvd.,
R-6600 Iasi, Romania. Tel.: +40 32 130680; Fax: +40 32 231132; E-mail:
hchiriac@phys-iasi.ro
Abstract: Extensive magnetic studies on
Nd_{90-x}Fe_{x}Al_{10}
(x = 35 ∼ 50) amorphous alloys in the shape of both
melt-spun ribbons with thicknesses between 25 and 150 μm
and rods with diameters no larger than 3~mm prepared by mould casting and
suction casting indicate a complex magnetic behaviour depending on the Fe
content. The microstructure and magnetic properties are strongly dependent on
the cooling rate and the preparation technique. The high values of the coercive
field of
Nd_{90-x}Fe_{x}Al_{10}
amorphous samples in the as-cast state as well as their increase by the
decrease of the cooling rate and temperature result from the formation of very
small metastable or non-equilibrium clusters, whose size vary as a function of
the quench rate. The presence of these magnetic clusters is evidenced by
multiphase magnetic transitions observed from the ac-susceptibility
measurements at low temperatures.
