Role of Stress in Thin Film Alloy Thermodynamics: Competition between Alloying and Dislocation Formation

Abstract

Using scanning tunneling microscopy (STM) and first-principles local-spin-density-approximation calculations to study submonolayer films of Co (1-c)Ag (c)/Ru(0001) alloys, we have discovered a novel phase-separation mechanism. When the Ag concentration c exceeds 0.4, the surface phase separates between a dislocated, pure Ag phase and a pseudomorphically strained Co(0.6)Ag (0.4) surface alloy. We attribute the phase separation to the competition between two stress relief mechanisms: surface alloying and dislocation formation. The agreement between STM measurements and our calculated phase diagram supports this interpretation.

Modelling the magnetorefractive effect in giant magnetoresistive granular and layered materials

“…The simplest relationship between the MRE and GMR is obtained by applying a binomial expansion to first order (written MRE ð1Þ HR ) to give: the l À1/2 behaviour of the Z-L-G plot as indicated in Eqs. (19) and (20). The discrepancy in magnitude at IR wavelengths beyond the minimum, but below approximately 80 mm remains, due to an underestimation of the reflectivity R H HR in applied magnetic fields.…”

“…6F FM a 0 =d 0 l interf ð1 þ p 2 s Þ, the lattice parameter of the granular interfaces a 0 , taken here to be a 0 % 2:7Å as the average distance between nearest neighbours in Co X Ag (1ÀX) alloys [20];…”

Interplay of strain relaxation and chemically induced diffusion barriers: Nanostructure formation in 2D alloys

“…For instance, it is an interesting open question, whether the model displays the concentration dependent competition between alloying and dislocation formation in island growth, which has been reported for CoAg/Ru(0001) [5]. A case of particular interest is that of an anisotropic substrate which favors the self-assembly of aligned stripes [4].…”

“…Among these are, e.g., the self-organized formation of three-dimensional islands, socalled Quantum Dots [2], self-assembly of ordered nanoscale domain patterns [3] or lateral multilayers [4], or the emergence of misfit dislocations [5]. New kinds of materials with unique properties have been fabricated and numerous technical applications are based on hetero-systems.…”

Phase composition and magnetic characteristics of Fe-filled multi-walled carbon nanotubes

“…(ii) The solubility of C in Fe can be strongly influenced by different quenching and stress effects during the synthesis process, like in the case of other nano-sized objects [8] and thus, the a-Fe(C) 3 g-Fe(C) transition temperature could be significantly reduced.…”