Despite much investigation of the electrochromic (EC) coloration process in WO3 films, such displays have not yet become commercially viable because of limited useful device life. Device degradation occurs by WO3 film dissolution on the shelf and erosion during cycling. Water plays a crucial role in both efficient coloring/bleaching and in film degradation. To better understand the degradation process and the role of water, dissolution of EC WO3 films in aqueous media was studied. The results strongly suggest that EC films formed by evaporation are amorphous molecular solids consisting of trimeric W3O9 molecules bound weakly to each other through water‐bridge, hydrogen, and van der Waal's bonding. The nature of this microstructure is responsible for the high solubility. Films subjected to ion bombardment show decreased dissolution rates as well as decreased electrochromism and, while amorphous, are believed to have a random network rather than molecular microstructure.

This article reports on the properties of the media prepared on glass substrates which were used in IBM’s 10 Gbit/in.2 demonstration. In order to support a linear density of 315 kbpi and a track density of 33 ktpi, the remanant coercivity Hcr and remanant moment thickness product Mrt of the magnetic layer were 3450 Oe and 0.37 memu/cm2, respectively. The media used a NiAl seed layer, a CrV underlayer, a Co alloy magnetic layer, and a carbon overcoat protection layer. The magnetic film had a grain size of 12 nm as observed by transmission electron microscopy. The preferred orientation (PO) of the magnetic layer was (101̄0). This PO enables one to sustain high coercivities at low values of Mrt. It is observed that the c-axis in-plane texture of the magnetic layer is critical to achieve a low noise medium. Using a focused-ion-beam (FIB) trimmed giant magnetoresistance head and conventional partial response maximum likelihood channel, the on-track-error rates were measured at the 10−10 level.

Thermal stability will ultimately limit the maximum areal density achievable with conventional longitudinal recording.The key aspects of the media microstructure contributing to thermal stability are the grain size and grain size distribution, alloy composition, alloy segregation, lattice defects and strain. Grain size distributions are created by the random nucleation processes occurring during media deposition. For media on glass substrates, -axis in-plane preferred orientation can be achieved with either Co (1120) or (1010) planes parallel to the substrate surface. Improved squareness, , is observed with the (1120) orientation due to stronger crystallographic texture, however, larger changes in coercivity with decreasing magnetic layer thickness are observed compared to (1010). Continued increases in areal density will require tighter grain size distributions and improved microstructural control of very thin magnetic layers.

Electrical properties of amorphous evaporated electrochromic MoO3 (molybdenum trioxide) films were studied in various ambients. It is shown that at a given applied voltage there is a “humidity threshold” below which coloration does not occur. The transient behavior of the current and remnant voltage in low humidity (precoloration), high humidity (postcoloration), and in the transition stage is shown to be consistent with an electrochemical interpretation of the coloration process. Changes in solubility upon electrical coloration and u.v. photocoloration verify that a chemical change accompanies the color change.