On the growth and magnetic properties of flower-like nanostructures formed on diffusion of FePt with Si substrate

Production of a magnetic material with the ability to change from very soft to semi-hard magnetic

“…The trends in the variation of H c and M s with T a are similar to nano-crystalline FeBPCu alloy. 7 However, after crystallization of a-Fe (at T a ¼ 430 C), the minimum H c is $30 A/m, which is slightly higher than the as-quenched state ($20 A/m). This is due to low volume fraction of a-Fe.…”

“…More diffraction peaks in addition to a-Fe ones have been observed on increasing T a up to 520 C. These diffraction peaks shift toward the higher angle (2h), as the T a increases to 570 and 700 C. Indexing of these peaks with known XRD data revealed formation of FePt phases. 3,4,7 The equi-atomic FePt has two phases, i.e., face centered cubic (fcc) and the L1 0 . The fcc phase is disordered, and the L1 0 is chemically ordered.…”

“…A minor presence of FePt phase is clearly visible at T a ¼ 430 C. Magnetic properties of ordered L1 0 and disordered fcc phases of FePt are known to be very different. 4,7 The disordered phase is magnetically soft, whereas the L1 0 phase is hard. Therefore, magnetic hysteresis curves were measured for the ribbons annealed at different T a .…”

“…We have noticed that Si can easily diffuse into the L1 0 FePt phase, and degrade the hard magnetic properties. 7 Thus, the alloy without Si is preferred. It is also reported that the excellent soft magnetic properties similar to FeSiBPCu can be obtained in Si free FeBPCu nano-crystalline alloys.…”