Pulsed laser deposition assisted fabrication and characterization of Fe–Co nanoparticles embedded in TiN thin film matrix

The FeCo material was synthesized in nanoparticle form in a TiN/FeCo/TiN sandwich structure using a pulsed laser deposition (PLD) method. FeCo is significantly cheaper than noble metal based bimetallic materials such as Fe–Pt, Ni–Pd, etc. A Fe0.5 Co0.5 composition was chosen in this study which is based on the local spin-density electronic-structure calculations. The advantage of this structure is in-situ passivation of FeCo nanoparticles by TiN thin films which is highly stable against atmospheric ambient conditions. TiN/FeCo/TiN samples with variable FeCo nanoparticle size were made by changing the number of laser pulses impinging on a chemically synthesized composite FeCo target. By controlling the particle size in the confined layers, it was possible to tune the magnetic properties from superparamagnetic to ferromagnetic in a controlled way. Magnetic hysteresis characteristics below the blocking temperature are consistent with single-domain behavior.

► TiN/FeCo/TiN structure using FeCo nanoparticles (NP) made by pulsed laser deposition
► In-situ passivation of FeCo NP is highly stable against atmospheric conditions.
► FeCo NP size controlled by number of laser pulses impinging on composite FeCo target
► Magnetic properties controlled by particle size in the confined layers