Title :
Aging effect on coercivity of iron oxide thin films
Author :
Ishii, Osamu ; Terada, Akira ; Ohta, Satoshi
Author_Institution :
NTT Interdisciplinary Res. Labs., Ibaraki, Japan
fDate :
5/1/1994 12:00:00 AM
Abstract :
Changes in magnetic properties for Fe3-x□x O4 (x: oxidation degree) thin films made by reactive sputtering and subsequent heat treatments have been examined under room temperature aging and constant temperature annealing. Aging causes variations in coercivity of insufficiently oxidized films which have a specific resistance of less than 1×101 Ω·cm, while the coercivity of γ-Fe2O3 (x=1/3) did not change. This phenomenon did not depend on additive elements or preparation method. Other magnetic properties such as saturation magnetization, residual magnetization, squareness ratio and coercive squareness, were not affected by aging for any Fe3-x □xO4 composition. The activation energy for a coercivity change is 0.72-0.95 eV near room temperature for films with a specific resistance below 1×101 Ω·cm. It was confirmed that only the coercivity varied at 20°C, while both coercivity and the degree of oxidation changed with annealing at 100°C
Keywords :
ageing; annealing; coercive force; iron compounds; magnetic thin films; sputtered coatings; 0.72 to 0.95 eV; 100 degC; 20 degC; Fe3-x□xO4 thin films; Fe3O4; activation energy; aging effect; coercivity; constant temperature annealing; heat treatments; reactive sputtering; room temperature aging; specific resistance; Aging; Annealing; Coercive force; Iron; Magnetic films; Magnetic properties; Oxidation; Sputtering; Temperature; Transistors;
Journal_Title :
Magnetics, IEEE Transactions on
