Effect of chromium interlayer on magnetic exchange coupling of SmCo/Cr/TbFeCo multilayer thin films

A series of SmCo/Cr/TbFeCo multilayer thin films with perpendicular anisotropy were prepared by RF- magnetron sputtering system, and the effects of Cr interlayer thickness on magnetic properties and interlayer exchange coupling were investigated. It was found that the magnetic properties varied with the thickness of Cr interlayer, especially the values of saturation magnetization Ms and the coercivity Hc fluctuated periodically with the thickness of Cr interlayer. STM images revealed that the variation of coercivity Hc was attributed to the microstructure change of SmCo layer influenced by Cr interlayer, and the variation of Ms was related to interlayer exchange coupling.

Effect of Ag Addition on the Microstructure and Magnetic Properties of FePt Thin Films

FePt thin films and [FePt/Ag]n multilayer thin films were prepared by magnetron sputtering technique and subsequent annealing process. By comparing the microstructure and magnetic properties of these two kinds of thin films, effects of Ag addition on the structure and properties of FePt thin films were investigated. Proper Ag addition was found helpful for FePt phase transition at lower annealing temperature. With Ag addition, the magnetic domain pattern of FePt thin film changed from maze-like pattern to more discrete island-like domain pattern in [FePt/Ag]n multilayer thin films. In addition, introducing nonmagnetic Ag hindered FePt grains from growing larger. The in-depth defects in FePt films and [FePt/Ag]n multilayer films verify that Ag addition is attributed to a large number of pinning site defects in [FePt/Ag]n film and therefore has effects on its magnetic properties and microstructure.

The interface density dependence of the electrical properties of 0.9Pb(Sc_(0.5)Ta_(0.5))O_3–0.1PbTiO_3/0.55Pb(Sc_(0.5)Ta_(0.5))O_3–0.45PbTiO_3 multilayer thin films

The 0.9Pb（Sc0.5Ta0.5）O3-0.1PbTiO3/0.55Pb（Sc0.5Ta0.5）O3-0.45 PbTiO3 multilayer thin films（（PSTT10/45）n, n = 1-6, 10） are deposited on SiO2/Si（100） substrates by radio frequency magnetron sputtering technique with La Ni O3 buffer and electrode layer, and the films are subsequently annealed by a two-step rapid thermal approach. It is found that the interfacial density of the film has an important influence on the electric property of the film. The electric property of the film increases and reaches its critical point with the increase of interface density, and then decreases with the further increase of the interface density. With an interfacial density of 16 μm-1, the film shows an optimized dielectric property（high dielectric constant, εr = 765, lowest dielectric loss, tan δ = 0.041, at 1 k Hz） and ferroelectric property（highest remnant polarization,2Pr = 36.9 μC/cm2, low coercive field, 2Ec = 71.9 k V/cm）. The possible reason for the electric behavior of the film is the competition of the interface stress with the interface defect.

Characteristics of Sb6Te4/VO2 Multilayer Thin Films for Good Stability and Ultrafast Speed Applied in Phase Change Memory

The Sb6 Te4/VO2 multilayer thin films are prepared by magnetron sputtering and the potential application in phase change memory is investigated in detail. Compared with Sb6 Te4, Sb6 Te4/VO2 multilayer composite thin films have higher phase change temperature and crystallization resistance, indicating better thermal stability and less power consumption. Also, Sb6 Te4/VO2 has a broader energy band of 1.58 eV and better data retention （125℃ for 103/）. The crystallization is suppressed by the multilayer interfaces in Sbf Te4/VO2 thin film with a smaller rms surface roughness for Sbf Te4/VO2 than monolayer Sb4Te6. The picosecond laser technology is applied to study the phase change speed. A short crystallization time of 5.21 ns is realized for the Sb6Te4 （2nm）/VO2 （8nm） thin film. The Sb6 Te4/VO2 multilayer thin film is a potential and competitive phase change material for its good thermal stability and fast phase change speed.

Electron-beam irradiation induced optical transmittance enhancement for Au/ITO and ITO/Au/ITO multilayer thin films

Electron beam（EB） irradiation experiments on Au/ITO and ITO/Au/ITO multilayer thin films are reported.The structure and the optical-electrical properties of the samples were investigated by X-ray diffraction,atomic force microscopy, four-point probe resistivity measurement system, and UV–vis-NIR double beam spectrometer, respectively. Those results show that the EB irradiation has the effects of improving the crystalline of samples, widening the optical band gap of both thin films, reducing the sheet resistance,and improving the transmittance of samples.

Flexible tuning microwave permeability spectrum in [ferromagnet/antiferromagnet]_n exchange-biased multilayer stack structure

NiFe/[IrMn/NiFe/IrMn] 5 /[NiFe/IrMn] 4 /NiFe structured exchange-biased multilayer films are designed and prepared by magnetron sputtering. The static and the microwave magnetic properties are systematically investigated. The results reveal that adding a partially pinned ferromagnetic layer can effectively broaden the ferromagnetic resonance linewidth toward the low frequency domain. Moreover, a wideband multi-peak permeability spectrum with a 3.1-GHz linewidth is obtained by overlapping the spectra of different partially pinned ferromagnetic layers and [antiferromagnet/ferromagnet/antiferromagnet] n stacks. Our results show that the linewidth of the sample can be feasibly tuned through controlling the proper exchange bias fields of different stacks. The designed multilayered thin films have potential application for a tunable wideband high frequency noise filter.

Characteristic modification by inserted metal layer and interface graphene layer in ZnO-based resistive switching structures

ZnO-based resistive switching device Ag/ZnO/TiN, and its modified structure Ag/ZnO/Zn/ZnO/TiN and Ag/graphene/ZnO/TiN, were prepared. The effects of inserted Zn layers in ZnO matrix and an interface graphene layer on resistive switching characteristics were studied. It is found that metal ions, oxygen vacancies, and interface are involved in the RS process. A thin inserted Zn layer can increase the resistance of HRS and enhance the resistance ratio. A graphene interface layer between ZnO layer and top electrode can block the carrier transport and enhance the resistance ratio to several times. The results suggest feasible routes to tailor the resistive switching performance of ZnO-based structure.