Anomalous magnetic behavior in MnFePSi glass-coated microwires

Abstract

We studied the MnFePSi glass-coated microwires (GCMWS) prepared by using Taylor–Ulitovsky technique at low magnetic fields and low temperatures. While regular ferromagnetic behavior has been observed at room temperature, anomalous magnetic behavior is observed for the glass-coated microwires samples. Notable metamagnetic phase transition is observed for bulk alloy sample from the magnetic hysteresis loops measured at 5 K. Meanwhile, extraordinary metamagnetic phase transition is seen at hysteresis loops measured at temperature below 100 K. In addition, M-H loops show harder magnetic properties compared to the bulk sample, where the coercivity, Hc, of glass-coated microwire is about 64 times higher than the one reported in bulk alloy. Additionally, the hysteresis loops of glass-coated microwires measured at temperature lower than 100 K show multistep magnetic behaviour. Zero Field Cooling (ZFC), Field Cooling (FC) and Field Heating (FH) curves of bulk samples show totally different magnetic behaviour compared to the microwire sample measured at the same conditions due to the different microstructure phases for the bulk and microwires samples. The present findings demonstrate the significant impact of drawing, quenching and stresses induced by glass-coating on the microstructure and magnetic characteristics of MnFePSi-metallic alloys as compared to their bulk form. Furthermore, we confirmed that, in contrast to the bulk form constraint, the Taylor-Ulitovsky process for metallic glass-coating microwires may alter the physical characteristics and extend the applications of MnFePSi alloys.