Magnetic hardening of Fe-Pt and Fe-Pt- M (M=B, Si) microwires.

We have prepared Fe-Pt and Fe-Pt- M (M = B, Si) microwires using Taylor-Ulitovsky technique and studied their magnetic properties. Magnetic properties considerably depend on the metallic core composition and annealing conditions. As-prepared microwires present either amorphous or mixture of amorphous and nanocrystalline phases with a presence of BCC FePt, FCC PtFe and small amount of tetragonal FePt phase. After annealing at 500 °C Fe 50 Pt 40 Si 10 microwires we observed a remarkable magnetic hardening (coercivity increasing from 5 Oe up to 500 Oe) related to crystallization of as-prepared amorphous Fe 50 Pt 40 Si 10 microwires. Annealed Fe 50 Pt 50 sample present coercivity up to 800 Oe at 5K, but the magnetization of Fe 50 Pt 50 sample is low and rapidly decreases with temperature. We discussed peculiarity of Fe 50 Pt 50 microwires considering the influence of internal stresses on magnetic ordering of Fe-atoms. [ABSTRACT FROM AUTHOR]