Multifunctional epitaxial systems on silicon substrates

Marco

Applied Surface Science

et al. 2018

Epitaxial cobalt ferrite thin films with strong in-plane magnetic anisotropy have been grown on Si (001) substrates using a TiN buffer layer. The epitaxial films have been grown by ion beam sputtering using either metallic, CoFe 2 , or ceramic, CoFe 2 O 4 , targets. X-ray diffraction (XRD) and Rutherford spectroscopy (RBS) in random and channeling configuration have been used to determine the epitaxial relationship CoFe 2 O 4 [100] / TiN [100] / Si [100]. Mössbauer spectroscopy, in combination with XRD and RBS, has been used to determine the composition and structure of the cobalt ferrite thin films. The TiN buffer layer induces a compressive strain in the cobalt ferrite thin films giving rise to an in-plane magnetic anisotropy. The degree of in-plane anisotropy depends on the lattice mismatch between CoFe 2 O 4 and TiN, which is larger for CoFe 2 O 4 thin films grown on the reactive sputtering process with ceramic targets.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Epitaxial integration of CoFe2O4 thin films on Si (001) surfaces using TiN buffer layers

Marco

Applied Surface Science

et al. 2018

Acta Crystallogr Sect B

“…The misfits are defined as 1 = (|a 1 | À |b 1 |)/|b 1 |*100%, 2 = (|a 2 À b 2 |/|b 2 |)*100%, a 1 is the close-packed vector length in the surface unit cell of the first crystal, b 1 refers to the second one, a 2 and b 2 refer to the second pair of any vector in the first and the second phase, respectively. For the criterion of a maximal misfit value, a rather conservative value of 5% was chosen, while the results for 4 and 7% show good qualitative convergence within the range of a typical misfit value, when one can expect epitaxial single crystal growth (Singamaneni et al, 2016).…”

Section: Finding Interface Orsmentioning

confidence: 99%

Prediction of orientation relationships and interface structures between α-, β-, γ-FeSi₂ and Si phases

Visotin

Тарасов

Федоров

et al. 2020

A pure crystallogeometrical approach is proposed for predicting orientation relationships, habit planes and atomic structures of the interfaces between phases, which is applicable to systems of low-symmetry phases and epitaxial thin film growth. The suggested models are verified with the example of epitaxial growth of -,and -FeSi 2 silicide thin films on silicon substrates. The density of near-coincidence sites is shown to have a decisive role in the determination of epitaxial thin film orientation and explains the superior quality of -FeSi 2 thin grown on Si(111) over Si(001) substrates despite larger lattice misfits. Ideal conjunctions for interfaces between the silicide phases are predicted and this allows for utilization of a thin buffer -FeSi 2 layer for oriented growth of -FeSi 2 nanostructures on Si(001). The thermal expansion coefficients are obtained within quasi-harmonic approximation from the DFT calculations to study the influence of temperature on the lattice strains in the derived interfaces. Faster decrease of misfits at the -FeSi 2 (001)||Si(001) interface compared to -FeSi 2 (001)||Si(001) elucidates the origins of temperature-driven change of the phase growing on silicon substrates. The proposed approach guides from bulk phase unit cells to the construction of the interface atomic structures and appears to be a powerful tool for the prediction of interfaces between arbitrary phases for subsequent theoretical investigation and epitaxial film synthesis. M. A. Visotin et al. -, -, -FeSi 2 and Si phases 471 research papers Acta Cryst. (2020). B76, 469-482 M. A. Visotin et al. -, -, -FeSi 2 and Si phases 473 research papers Acta Cryst. (2020). B76, 469-482 M. A. Visotin et al. -, -, -FeSi 2 and Si phases 479 Figure 6Temperature dependence of interface strain" " for different silicon||silicide and silicide||silicide ORs from Table 1. research papers Acta Cryst. (2020). B76, 469-482 M. A. Visotin et al. -, -, -FeSi 2 and Si phases 481

J of Applied Polymer Sci

“…However, to date, a very limited number of organic and organometallic MFs have been discovered and investigated; we have been responsible for all of the published results. These are MFs based on organometallic complexes, in which polarization occurs via proton transfer in (Me 2 NH 2 )─M─(HCO 2 ) 3 formiate complexes (where M is Mn, Co, or Ni) . Another example is a compound with the reversible shift of the oxygen atom between Mn or Co in binuclear Mn(II)─O─Mn(II) and Co(II)─O─Co(II) complexes; these exhibit the ME effect due to a change in the exchange and spin‐orbit interactions after the shift in the charge and spin densities .…”

Section: Introductionmentioning

confidence: 99%

Silicon core–iron siloxane shell nanoparticle polymer composites with multiferroic properties

Aleksandrov

Шевченко

Aleksandrov

et al. 2019

Multiferroic (MF) composites based on nanoparticles consisting of a silica core and a shell of spin‐variable Fe(III) complexes in a polymer matrix (polystyrene) were synthesized and characterized by different methods. The nanoparticles had the formula 80SiO2·20{Fe[OSi(Me)(OEt)2]3}, and their particle size was on the order of 5–7 nm. Dielectric and electron spin resonance studies showed the presence of two types of Fe ions in the nanocomposite. Iron ions in the low‐spin state [Fe(III)‐LS] and iron ions in the high‐spin state [Fe(III)‐HS], which were bound by indirect exchange interactions through oxygen and silicon atoms {[Fe(III)‐LS]─O─Si─O─[Fe(III)‐HS]} were responsible for the MF properties of the composites with core–shell nanoparticles. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47681.