Magnetic and Microwave Properties of FeNi Thin Films of Different Thicknesses Deposited Onto Cyclo Olefin Copolymer Flexible Substrates

Thin Fe19Ni81 films were deposited by magnetron sputtering technique onto cyclo olefin (COC) flexible polymer substrates. COC/FeNi(15 nm), COC/FeNi(23 nm), COC/FeNi(25 nm) and COC/FeNi(84 nm) composites were obtained and studied using structural, magnetic and microwave measurements. COC/FeNi(84 nm) composite, which still had certain transparency insured a complete protection with respect to the component of microwave signal polarized along the gunn diode axis (frequency of 10.52 GHz). Even most thin (15 nm) FeNi film was almost as effective as 84 nm film but having much higher transparency acceptable for microfluidic devices. Obtained results indicate that fabricated flexible composites can be used as effective shielding materials in complex multipurpose devices.