Structural and magnetic properties of E-Fe_{1-x}Co_xSi thin films deposited via pulsed laser deposition

TL;DR

This study demonstrates the successful synthesis of dense, smooth Fe1-xCoxSi thin films with cubic B20 structure via pulsed laser deposition, revealing a transition from helimagnetism to ferromagnetism in thin films, unlike bulk properties.

Contribution

First report of pulsed laser deposited Fe1-xCoxSi thin films showing a magnetic phase transition from helimagnetism to ferromagnetism.

Findings

Films are dense, smooth, and single-phase.

All films exhibit ferromagnetism, including pure FeSi.

Transition from helimagnetism in bulk to ferromagnetism in thin films.

Abstract

We report pulsed laser deposition synthesis and characterization of polycrystalline Fe1-xCox Si thin films on Si (111). X-ray diffraction, transmission electron, and atomic force microscopies reveal films to be dense, very smooth, and single phase with a cubic B20 crystal structure. Ferromagnetism with significant magnetic hysteresis is found for all films including nominally pure FeSi films in contrast to the very weak paramagnetism of bulk FeSi. For Fe1-xCoxSi this signifies a change from helimagnetism in bulk, to ferromagnetism in thin films. These ferromagnetic thin films are promising as a magnetic-silicide/silicon system for polarized current production, manipulation, and detection.