5$μ$m thick SmCo films were deposited onto Si substrates using triode sputtering. A study of the influence of deposition temperature (Tdep <= 600 degrees C) on the structural, magnetic and mechanical properties has shown that optimum properties (highest degree of in-plane texture, maximum in-plane coercivity and remanence (1.3 and 0.8 T, respectively), no film peel-off) are achieved for films deposited at the relatively low temperature of 350 degrees C. This temperature is compatible with film integration into Micro-Electro-Mechanical-Systems (MEMS). The deposition rate was increased from 3.6 to 18 $μ$m/h by increasing the surface area of the target from 7 to 81 cm2. Mechanically stable films could be prepared by deposition onto pre-patterned films or deposition through holes in a mask.
High-pressure torsion (HPT), a technique of severe plastic deformation (SPD), is shown as a promising processing method for exchange-spring magnetic materials in bulk form. Powder mixtures of Fe and SmCo$_{5}$ are consolidated and deformed by HPT exhibiting sample dimensions of several millimetres, being essential for bulky magnetic applications. The structural evolution during HPT deformation of Fe-SmCo$_{5}$ compounds at room- and elevated- temperatures of chemical compositions consisting of 87, 47, 24 and 10 wt.% Fe is studied and microstructurally analysed. Electron microscopy and synchrot…
The characteristic microstructure of Sm(Co,Fe,Cu,Zr)$_z$ alloys with SmCo$_5$ cell walls in Sm$_2$Co$_{17}$ cells, all intersected by Zr-rich platelets, makes them some of the best performing high-temperature permanent magnets. Plentiful research has been performed to tailor the microstructure at the nanoscale, but due to its complexity many questions remain unanswered about the effect of the individual phases on the magnetic performance at different temperatures. Here, we explore this mechanism effect for three different Sm(Co,Fe,Cu,Zr)$_z$ alloys by deploying high-resolution magnetic imaging…
Atomic-scale computational modeling of technologically relevant permanent magnetic materials faces two key challenges. First, a material's magnetic properties depend sensitively on temperature, so the calculations must account for thermally induced magnetic disorder. Second, the most widely-used permanent magnets are based on rare-earth elements, whose highly localized 4$f$ electrons are poorly described by standard electronic structure methods. Here, we take two established theories, the disordered local moment picture of thermally induced magnetic disorder and self-interaction-corrected dens…
We investigate the electronic structure of tungsten ditelluride (WTe$_2$) flakes with different thicknesses in magneto-transport studies. The temperature-dependent resistance and magnetoresistance (MR) measurements both confirm the breaking of carrier balance induced by thickness reduction, which suppresses the `turn-on' behavior and large positive MR. The Shubnikov-de-Haas oscillation studies further confirm the thickness-dependent change of electronic structure of WTe$_2$ and reveal a possible temperature-sensitive electronic structure change. Finally, we report the thickness-dependent aniso…
The electrocaloric effect of BaTiO3 multilayer thick film structure was investigated by direct measurement and theoretical calculation. The samples were prepared by the tape-casting method, which had 180 dielectric layers with an average thickness of 1.4μm. The thermodynamic calculation based on the polarization- temperature curves predicted a peak heat adsorption of 0.32J/g at 80^\circC under 176kV/cm electric field. The direct measurement via differential scanning calorimeter showed a much higher electrocaloric effect of 0.91J/g at 80^\circC under same electric field. The difference could re…
The atomic structure and physical properties of few-layered <111> oriented diamond nanocrystals (diamanes), covered by hydrogen atoms from both sides are studied using electronic band structure calculations. It was shown that energy stability linear increases upon increasing of the thickness of proposed structures. All 2D carbon films display direct dielectric band gaps with nonlinear quantum confinement response upon the thickness. Elastic properties of diamanes reveal complex dependence upon increasing of the number of <111> layers. All theoretical results were compared with available experi…
Amorphous/crystalline multilayer structures of Fe-P alloys were deposited electrochemically using the single bath technique. Hall-Petch behavior of microhardness with respect to sublayer thickness was observed down to a sublayer thickness of 15 nm. For thinner sublayers, a hardness plateau was obtained. The transition at a sublayer thickness of 15 nm coincides with the loss of the multilayer structure as observed in transmission electron microscopy. The transition is a possible result of a change in the amorphous to crystalline sublayer thickness ratio and the interface roughness development d…
Growth, electronic and magnetic properties of $γ'$-Fe$_{4}$N atomic layers on Cu(001) are studied by scanning tunneling microscopy/spectroscopy and x-ray absorption spectroscopy/magnetic circular dichroism. A continuous film of ordered trilayer $γ'$-Fe$_{4}$N is obtained by Fe deposition under N$_{2}$ atmosphere onto monolayer Fe$_{2}$N/Cu(001), while the repetition of a bombardment with 0.5 keV N$^{+}$ ions during growth cycles results in imperfect bilayer $γ'$-Fe$_{4}$N. The increase in the sample thickness causes the change of the surface electronic structure, as well as the enhancement in …
Three new single-atom-thick silicon-carbon stable systems have been found by using of SCED-LCAO and DFT methods. An important position, named bone position, is proposed in these structures. For SiC and Si1C9 system, the bone positions are partially occupied by Si atoms, the plane structure is kept and electronic gap is opened with 0.955 eV and 0.689 eV respectively. For Si2C8 system, the bone positions are fully occupied by Si atoms. It shows a buckled structure with a buckling of 0.05 Å and a Dirac cone at M point. Moreover, the sp hybridization between Si and C atoms in SiC system is found a…
We discuss the structural and electronic properties of tetragonal CuO grown on SrTiO3(100) by means of hybrid density functional theory. Our analysis explains the anomalously large Cu-O vertical distance observed in the experiments (~2.7 A) in terms of a peculiar frustration between two competing local Cu-O environments characterized by different in-plane and out-of-plane bond lengths and Cu electronic populations. The proper inclusion of substrate effects is crucial to understand the tetragonal expansion and to reproduce correctly the measured valence band spectrum for a CuO thickness of 3-3.…
Both the semi-classical and quantum transport properties of F-doped SnO$_2$ thick films ($\sim$1\,$μ$m) were investigated experimentally. It is found that the resistivity caused by the thermal phonons obeys Bloch-Grüneisen law from $\sim$90 to 300\,K, while only the diffusive thermopower, which varies linearly with temperature from 300 down to 10\,K, can be observed.The phonon-drag thermopower is completely suppressed due to the long electron-phonon relaxation time in the compound. These observations, together with the temperature independent characteristic of carrier concentration, indicate t…
We study the thickness dependence of the electronic, magnetic, and optical properties of a NiPS$_3$ thin film, an antiferromagnetic charge-transfer insulator. Utilizing state-of-the-art advanced density functionals, we find the antiferromagnetic Zig-Zag order, the band gap, and the main peaks in the dielectric tensor are all in good agreement with the corresponding experimental values. Upon thinning, the Zig-Zag antiferromagnetic order becomes virtually degenerate with a competing Néel order, consistent with the suppression of long-range order observed by Raman spectroscopy due to strong magne…
We have studied the processing of piezoelectric thick films using electrophoretic deposition (EPD) for high-frequency ultrasound applications. Lead-zirconium-titanate (PZT) particles synthetized by solid states synthesis were dispersed in ethanol using ammonium polyacrylate (PAA). The electrophoretic deposition of PZT particles was performed at a constant-current mode. PZT thick-films deposited at 1 mA for 60 seconds were sintered at 900oC for 2 hours in a PbO-controlled atmosphere. The scanning-electron microscopy (SEM) analysis shows that the thickness of PZT layer is uniform and that the po…
