Development of Hysteresis in Ball-Milled LaCo5-xFex and La2Co7-xFex

The magnetic and structural properties of bulk, ball-milled La(Co_5-xFe_x), and ball-milled La₂(Co_7-xFe_x) were studied. The highest coercivity (1.08 T) was obtained at room temperature for ball-milled LaCo_4.8Fe_0.2 after annealing in a preheated furnace at 800 °C for 3 min and subsequently quenching. Iron doping up to x = 1 increased the saturation magnetization by up to 20% without any deterioration of coercivity. For La₂(Co_7-xFe_x), the highest coercivity (1.2 T) at room temperature and (1.92 T) at 4 K was obtained for ball-milled La₂Co₇ after annealing in the preheated furnace at 850 °C for 3 min and subsequently quenching. Unlike Fe-doped LaCo₅, iron doping in La₂Co₇ did not enhance the saturation magnetization.