In this work, doping C and codoping C and N into the Sb2Te3 traditional chalcogenide were investigated to reduce the writing current of the phase-change device using a chalcogenide as the active medium. No face-centered-cubic (FCC) structure was observed in the C-doped Sb2Te3 film, while it appeared after codoping C and N into Sb2Te3. The FCC crystallite size greatly reduced from 6.5 to 3.5–3.8 nm after codoping. In particular, the resistivity of FCC C–N codoped Sb2Te3 was about two orders of magnitude higher than that of Sb2Te3. The effect of the property of the chalcogenide on the writing current of the phase-change device was analyzed by the finite element method. The analysis showed that the writing current of the device using C–N-codoped Sb2Te3 as the active medium can significantly drop to about 1/8 of that of the Sb2Te3 based one.

In this study, undoped Zn5Sb3Te (ZST) and N-Ti codoped ZST chalcogenides were investigated. The deposition rate of chalcogenides decreased when N and Ti were doped into ZST, caused by the low speed of reaction to form nitrides and the strong bond of Ti atoms, respectively. Surface roughness was significantly reduced to approximately one-seventh of the original value owing to the doping of N-Ti into ZST, implying high reliability. Based on X-ray diffraction and electrical measurements, the crystallization of ZST occurred after it was annealed at a high temperature between 250 ℃ and 300 ℃, while codoping N-Ti into ZST further increased the crystallization temperature to above 300 ℃. The crystallization temperature of N-Ti codoped ZST was approximately 150 ℃ higher than that of the conventional Ge2Sb2Te5 chalcogenide, indicating high thermal stability.

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The structure and magnetic properties are reported for Gd/Fe multilayers with periodic line patterns fabricated by alternating UHV evaporation combined with photolithography or interference lithography and liftoff. In cross-sectional TEM images, the Fe layers show a grain structure, while no contrast was observed in the Gd layers. Magnetic hysteresis measurements show that the coercive field increases with line periodicity and magnetic layer thickness. This behavior might be attributed to not only the demagnetization field, but also the pinning effects of the crystal grain boundaries on the domain walls, and/or the influence of exchange coupling at the interface between Fe and Gd layers.