Intersection Magnetization and Temperature Revealed by FCC-FCT Phase Transformation in the FePd Binary Alloy System

This study investigated the fcc-fct phase transformation effect on the magnetic properties of the FePd alloy system by means of the effective field theory (EFT) developed by Kaneyoshi (1993). We determined the thermal magnetization loop and magnetic hysteresis loop of fcc-FePd and fct-FePd for both the ferromagnetic (FM) and antiferromagnetic (AFM) case. We found that the FM fcc-FePd and fct-FePd have a single thermal magnetization area, whereas AFM fcc-FePd and fct-FePd have binary thermal magnetization area. In the AFM case, the magnetization curves for fcc-FePd and fct-FePd had an intersection temperature point (Ti = 1.33 at H = 0). At Ti, the magnetization value of the fcc-FePd and fct-FePd was almost the same (Mi = 0.59) and we call this magnetization the intersection magnetization. However, the magnetic hysteresis loop area of the fcc-FePd was higher than that of the fct-FePd for both the FM and AFM case. Fcc-fct phase transformation has a strong effect on the FM and AFM properties of the FePd binary alloy system.