Article comprising spinel-structure material on a substrate, and method

Abstract

Ferrite films having excellent crystalline and magnetic properties are obtainable without high temperature (>500.degree. C.) processing if an appropriate template layer is deposited on a conventional substrate body (e.g., SrTiO.sub.3, cubic zirconia, Si), and the ferrite is deposited on the annealed template. The template is a spinel-structure metal oxide that has a lattice constant in the range 0.79-0.89 nm, preferably within about 0.015 nm of the lattice constant of the ferrite. Exemplarily, a NiFe.sub.2 O.sub.4 film was deposited at 400.degree. C. on a CoCr.sub.2 O.sub.4 template which had been deposited on (100) SrTiO.sub.3. The magnetization of the ferrite film at 4000 Oe was more than double the magnetization of a similarly deposited comparison ferrite film (NiFe.sub.2 O.sub.4 on SrTiO.sub.3), and was comparable to that of a NiFe.sub.2 O.sub.4 film on SrTiO.sub.3 that was annealed at 1000.degree. C. The ability to produce ferrite films of good magnetic properties without high temperature treatment inter alia makes possible fabrication of on-board magnetic components (e.g., inductor) on Si chips designed for operation at relatively high frequencies, e.g., >10 MHz, even at about 100 MHz.