Application of inkjet technology for the deposition of magnetic nanoparticles to form micron-scale structures

Inkjet printing technique has been applied to the production of magnetic layers and structures consisting of nanosized magnetic particles. These magnetic particles were synthesised by chemical methods and dispersed in suitable fluidic systems. The rheological parameters of the fluids were adjusted for inkjet printing. The resulting micron-scale pattern were obtained with a high reproducibility and structure control. The magnetic local structure of the patterns has been studied by using a new local 'in-plane' susceptibility measurement system as well as magnetic force microscopy. The deposited structures reveal a chain-like self-alignment of the magnetic particles. Potential applications of this fast and versatile process are the production of low- and medium-density magnetic mass storage patterns on almost any kind of substrate and for magnetic character recognition purposes. Printed patterns with minimal structure dimensions in the range of 50-100 mum are discussed. Work is in progress to decrease these dimensions by an order of magnitude by volume reduction of the deposited ink droplets.