Prima-Garcia et al. Nanoscale Research Letters 2012, 7:232 http://www.nanoscalereslett.com/content/7/1/232 Page 3 of 4 Figure 1 AFM topography images. Surface of thin films of 1 obtained after different times of electrodeposition: (a) 10 s (80-nm thickness), (b) 2 s (50-nm thickness), and (c) 1 s (40-nm thickness). MOKE signal at a given energy of the incident light depends on the joint magneto-optical density of states. The magneto-optical response at 190 K of the thinner films of 1 with thicknesses ranging from 80 to 40 nm is depicted in Figure 2. In contrast with the SQUID measure- ments, where it was found to be independent of the film thickness, here, the coercive field suffers an important change in value when decreasing the film thickness (Table 1). This tendency has been studied [11]. In Figure 3, the coercive field is showed as a function of the mean grain size. When the particle size is reduced, the coercive field increases, passing through a maximum and then decreasing again. The magnetization reversal process for the particles composing the film is different in each region of the curve in Figure 3. The thicker films with a bigger grain size consist of relatively large multi-domain magnetic particles, whereas in the thinner films, the particles approach the single-domain limit, resulting in an increase in coercivity. Such a particle-size effect has been previously described in other molecule-based materials [13-15]. In consequence, there is an increase in coercive field with the reduction of the grain size until this value reaches a maximum, in our case 85 mT for a grain size of 170 nm; underneath this value, the physical processes associated to the magnetization reversal in smaller grains produce a reduction in coercive field. Conclusions In summary, it has been demonstrated in this work that it is possible to tune the thickness of electrodeposited films of Prussian blue analogues by changing the electro- deposition time. Therefore, it is possible to reach the nanometer scale in thin films of PBA by reducing the Figure 2 Normalized MOKE hysteresis loops. Obtained in polar configuration for three thin films of 1 of various thicknesses. Figure 3 Coercive field. As a function of the average grain size of thin films of 1 shown in Table 1.