Context :

Aims : The aim of this work is to present and discuss the observations of the iron peak ( Fe , Ni ) and neutron-capture element ( Y , Zr , Ba , La , Ce , Nd , Sm , and Eu ) abundances for 276 FGK dwarfs , located in the galactic disk with metallicity -1 < [ Fe/H ] < +0.3 .

Methods : Atmospheric parameters and chemical composition of the studied stars were determined from an high resolution , high signal-to-noise echelle spectra obtained with the echelle spectrograph ELODIE at the Observatoire de Haute-Provence ( France ) .
Effective temperatures were estimated by the line depth ratio method and from the H _ { \alpha } line-wing fitting .
Surface gravities ( \log~ { } g ) were determined by parallaxes and the ionization balance of iron .
Abundance determinations were carried out using the LTE approach , taking the hyperfine structure for Eu into account , and the abundance of Ba was computed under the NLTE approximation .

Results : We are able to assign most of the stars in our sample to the substructures of the Galaxy thick disk , thin disk , or Hercules stream according to their kinematics .
The classification of 27 stars is uncertain .
For most of the stars in the sample , the abundances of neutron-capture elements have not been measured earlier .
For all of them , we provide the chemical composition and discuss the contribution from different nucleosynthesis processes .

Conclusions :

The [ Ni/Fe ] ratio shows a flat value close to the solar one for the whole metallicity range , with a small scatter , pointing to a nearly solar Ni/Fe ratio for the ejecta of both core-collapse SN and SNIa .
The increase in the [ Ni/Fe ] for metallicity higher than solar is confirmed , and it is due to the metallicity dependence of ^ { 56 } Ni ejecta from SNIa .
Under large uncertainty in the age determination of observed stars , we verified that there is a large dispersion in the AMR in the thin disk , and no clear trend as in the thick disk .
That may be one of the main reasons for the dispersion , observed for the s -process elements in the thin disk ( e.g. , Ba and La ) , whereas much narrower dispersion can be seen for r -process elements ( e.g. , Eu ) .
Within the current uncertainties , we do not see a clear decreasing trend of [ Ba/Fe ] or [ La/Fe ] with metallicity in the thin disk , except maybe for super-solar metallicities .
We can not confirm an increase in the mentioned ratios with decreasing stellar age .