# First principles study of bimetallic Ni$_{13-n}$Ag$_n$ nano-clusters ($n =$ 0$-$13) : Structural, mixing, electronic and magnetic properties

## TL;DR

This study uses density functional theory to systematically analyze the structure, mixing, electronic, and magnetic properties of Ni-Ag nano clusters, revealing core-shell structures, favorable mixing energies, and magnetic interactions.

## Contribution

It provides the first comprehensive DFT-based analysis of all compositions of Ni$_{13-n}$Ag$_n$ nano clusters, highlighting structural preferences and magnetic behavior.

## Key findings

- Core-shell like structures are favored in all compositions.
- Negative mixing energies indicate stable alloy formation.
- Ni-Ag interfacial interactions influence magnetic properties.

## Abstract

Using spin polarized density functional theory (DFT) based calculations, combined with ab-initio molecular dynamics simulation, we carry out a systematic investigation of the bimetallic Ni$_{13-n}$Ag$_n$ nano clusters, for all compositions. This includes prediction of the geometry, mixing behavior, and electronic properties. Our study reveals a tendency towards formation of a core-shell like structures, following the rule of putting Ni in high coordination site and Ag in low coordination site. Our calculations predict negative mixing energies for the entire composition range, indicating mixing to be favored for the bimetallic small sized Ni-Ag clusters, irrespective of the compositions. The magic composition with the highest stability is found for the NiAg$_{12}$ alloy cluster. We investigate the microscopic origin of core-shell like structure with negative mixing energy, in which the Ni-Ag inter-facial interaction is found to play role. We also study the magnetic properties of the Ni-Ag alloy clusters. The Ni dominated magnetism, consists of parallel alignment of Ni moments while the tiny moments on Ag align in anti-parallel to Ni moments. The hybridization with Ag environment causes reduction of Ni moment.