Ba ferrite films with large saturation magnetization and high coercivity prepared by low-temperature sputter deposition

Ba ferrite films were deposited in a mixture of Xe, Ar, and O-2 by using facing targets sputtering apparatus with sintered targets of Fe-excessive BaM ferrite. By using Xe as sputtering gas, the bombardment of energetic Ar atoms recoiled from target to film surface was sufficiently suppressed and Fe content in Ba ferrite crystallites was significantly increased. It was found that the segregation of spinel crystallites among BaM ones were not observed and these BaM crystallites revealed the excellent c-axis orientation normal to film plane and clear perpendicular magnetic anisotropy. At substrate temperature T-s of 600 degrees C, saturation magnetization 4 pi M(s) of 5.1 kG, which is larger than that of BaM ferrite single crystal, and perpendicular coercivity H-c perpendicular to of 2.4 kOe were obtained. BaM ferrite films composed of well c-axis oriented crystallites with large perpendicular magnetic anisotropy constant, large saturation magnetization 4 pi M(s) of 4.7 kG and high perpendicular coercivity H-c perpendicular to of 2.4 kOe were obtained at substrate temperature T-s as low as 475 degrees C. (C) 1996 American Institute of Physics.