Vacuum chamber made of soft magnetic material with high permeability

► Permalloy (Ni-Fe-Mo) alloy and ferritic (Fe-Cr) stainless steel were selected for the vacuum chambers with high magnetic permeability. ► Outgassing rate of permalloy alloy with vacuum heat treatment is 1 · 10−8 Pa m/s. ► Magnetic annealing at a temperature higher than 850 °C is effective for the magnetic shielding. ► Heat treatment under high vacuum condition can be used as both magnetic annealing and outgassing reduction.