Substrate-induced antiferromagnetism of an Fe monolayer on the Ir(001) surface

We present detailed ab initio study of structural and magnetic stability of a Fe-monolayer on the fcc(001) surface of iridium. The Fe-monolayer has a strong tendency to order antiferromagnetically for the true relaxed geometry. On the contrary an unrelaxed Fe/Ir(001) sample has a ferromagnetic ground state. The antiferromagnetism is thus stabilized by the decreased Fe-Ir layer spacing in striking contrast to the recently experimentally observed antiferromagnetism of the Fe/W(001) system which exists also for an ideal bulk-truncated, unrelaxed geometry. The calculated layer relaxations for Fe/Ir(001) agree reasonably well with recent experimental LEED data. The present study centers around the evaluation of pair exchange interactions between Fe-atoms in the Fe-overlayer as a function of the Fe/Ir interlayer distance which allows for a detailed understanding of the antiferromagnetism of a Fe/Ir(001) overlayer. Furthermore, our calculations indicate that the nature of the true ground state could be more complex and display a spin spiral-like rather than a c(2x2)-antiferromagnetic order. Finally, the magnetic stability of the Fe monolayer on the Ir(001) surface is compared to the closely related Fe/Rh(001) system.Comment: 8 pages, 4 figure

Balances and Abelian Complexity of a Certain Class of Infinite Ternary Words

A word $u$ defined over an alphabet $\mathcal{A}$ is $c$-balanced ($c\in\mathbb{N}$) if for all pairs of factors $v$, $w$ of $u$ of the same length and for all letters $a\in\mathcal{A}$, the difference between the number of letters $a$ in $v$ and $w$ is less or equal to $c$. In this paper we consider a ternary alphabet $\mathcal{A}=\{L,S,M\}$ and a class of substitutions $\phi_p$ defined by $\phi_p(L)=L^pS$, $\phi_p(S)=M$, $\phi_p(M)=L^{p-1}S$ where $p>1$. We prove that the fixed point of $\phi_p$, formally written as $\phi_p^\infty(L)$, is 3-balanced and that its Abelian complexity is bounded above by the value 7, regardless of the value of $p$. We also show that both these bounds are optimal, i.e. they cannot be improved.Comment: 26 page

MARKETING RESEARCH ABOUT PERCEPTIONS OF PRODUCERS OF ROMANIAN TRADITIONAL PRODUCTS

The purpose of this study is to describe the businesses of Romanian producers of agrofood traditional products traded to the Romanian Farmer’s Fair. The need of pursuing these issues is emerged from the changes happened on the market of agro-food products in those regarding the transitions to a healthier consumption, to ecological and/or traditional products, in the case of some consumers. Because of these, some producers identified opportunities of developing businesses with traditional Romanian products. In describing producers’ businesses, a qualitative marketing research is undertaken to the Romanian Farmer’s Fair, trying to identify future trends of the market of agro-food products.Traditional products, Model of consumption, Agro-food products’ market, Consumer, Agribusiness, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,