Temperature Dependence Magnetoresistance of Fe_73.5 –Cu₁ –Ta₃ –Si_13.5 –B₉ Magnetic Alloy

M Z Ahsan, F A Khan and M. Perven

Abstract: Fe_73.5-Cu₁– Ta₃-Si_13.5-B₉ magnetic alloy, in the form of ribbon, was synthesized by single roller melt-spinning technique in air. The magneto transport properties of the sample were studied as a function of temperature using conventional 4-probe technique. The sample exhibits semiconducting behavior at low temperature (35 – 295 K) and metallic behavior at high temperature (350 – 700 K). The magnetoresistance (MR) found to increase with both the temperature and field in the low temperature range due to the ordering effect of microcrystallites in the amorphous matrix. A significant dispersion of negative MR obtained at 700 K due to more disorderliness of spins in the amorphous matrix of the sample. Its Zero Field Cool (ZFC) and field cool (FC) measurement demonstrates both the positive and negative slopes of Magnetoresistance below and above a critical transition temperature, 175 K that resulted from the difference of magnetic and thermal energies. Up to this critical temperature, the system makes a transition from ferromagnetic (FM) to antiferromagnetic(AFM) and above this temperature from AFM to FM, which is an indicative of reentrant ferromagnetic phase, which leads to be used it in sensors and magnetic devices.

Keywords: Magnetic alloy, Normalized resistivity, Magnetoresistance, Microcrystallites.

Pages: 272 – 278 | Full PDF Paper