Improvement of sputtered Galfenol thin films for sensor applications

Abstract

Galfenol Fe83Ga17 films are sputtered on Si wafers without, and with Ti or Ti/Cu metallic seed layers in order to obtain a magnetoelastic layer which is sensitive to bending deformations of the compound structure. The layer thicknesses range from 100?nm to 5? ?m. Layer morphology, texture, and the Villari effect are examined. The texture of the Galfenol films is strongly influenced by the seed layer. No low-index texture components are found for films directly deposited on Si and SiO2. On Ti, a (111) texture is formed on layers with more than 1000?nm thickness. A favorable (110) fiber texture is formed on Ti/Cu. Deforming the bimorphs (Si + layer system) by 0.012%, the Villari effect is detected due to the change in relative permeability. The maximum change occurs for Galfenol films with a thickness of 1? ?m on a Ti/Cu buffer layer. The films open a route to the incorporation of magnetoelastic films into integrated magnetoelastic sensor devices.