Effect of film thickness on the photoinduced decrease in magnetism for thin films of the cobalt iron prussian blue analogue Rb0.7Co4[Fe(CN)6]3.0

Abstract Films of the photomagnetic Prussian blue analogue Rb 0.7 Co 4 (Fe(CN) 6 ) 3.0 (Co–Fe PBA) were deposited onto a Melinex ® substrate using two different multiple sequential adsorption methods. Film thickness, measured using atomic force microscopy, was controlled by the number of deposition cycles. The photoinduced magnetism known for the bulk Co–Fe PBA at low temperatures is also seen in the thin films, although the response is anisotropic. A photoinduced increase in magnetization is observed when the film is parallel (∥) to the applied magnetic field ( H E ), while a photoinduced decrease is observed when the film is perpendicular (⊥) to a weak H E . The relationship between the film thickness and the photoinduced decrease in magnetization is explored in this article. The photoinduced decrease is observed for films less than ∼200 nm thick. The behavior is explained by invoking a dipolar interaction between primordial ferrimagnetic domains and the photoswitchable pairs arrayed in the quasi-2D thin film.