EPITAXIAL-GROWTH, STRUCTURE AND PROPERTIES OF NI FILMS GROWN ON MGO(100) BY DC BIAS SPUTTER-DEPOSITION

Ni films of 70-240 nm thickness were deposited on an MgO(100) substrate at temperatures T(s) greater-than-or-equal-to 190-degrees-C by d.c. sputtering at 2.5 kV in pure Ar gas. A negative bias voltage V(s) between zero and -110 V was applied to the substrate during the deposition. Reflection high energy electron diffraction, X-ray diffraction, cross-sectional transmission electron microscopy, Auger electron spectroscopy, ferromagnetic resonance and the measurement of the temperature coefficient of resistance were used to determine the structure and properties of the films. The degree of epitaxy of Ni increases with increasing T(s) as well as increasing V(s). The optimum conditions for epitaxial growth of Ni are T(s) greater-than-or-equal-to 280-degrees-C and V(s) greater-than-or-equal-to 80 V. In this range epitaxial films with Ni(100) parallel-to MgO(100) and Ni[100] parallel-to MgO[100] can be prepared. A magnetic anisotropy is induced in the film plane. This anisotropy may be a result of superposition of a magnetocrystalline anisotropy originating from the epitaxial Ni film and of a uniaxial magnetic anisotropy induced during the film formation. In conclusion, as V(s) ranges - 80 to - 110 V the bombarding effect of both energetic ions and fast neutrals of Ar will rule the epitaxial growth of the Ni film by increasing the mobility of Ni adatoms and by resputtering the impurities. This effect is pronounced at T(s) greater-than-or-equal-to 280-degrees-C.