Disclosed herein is a magnetic storage device that comprises a housing defining an interior cavity. The magnetic storage device also comprises at least one magnetic disk in the interior cavity of the housing. The magnetic storage device further comprises at least one read-write head in the interior cavity and configured to read data from and write data to the magnetic disk. The read-write head comprises a heat-assisted magnetic storage (HAMR) head. The magnetic storage device additionally comprises a gas, comprising oxygen and helium, sealed in the interior cavity of the housing. A percent concentration of oxygen in the gas is greater than or equal to 3%. A pressure of the gas is between 10% and 70%, inclusive, of atmospheric pressure. A relative humidity within the interior cavity is less than 5%, inclusive. A percent concentration of helium in the gas is less than or equal to 90%.