Magnetic Properties of Thin-Film Alloys

Magnetic thin films composed of binary and ternary alloys are central to advances in data storage, spintronics and sensing technologies. Their behaviour is governed by a combination of intrinsic factors—composition, crystal structure and magnetic ordering—and extrinsic factors such as film thickness, strain and interface quality. Alloying permits tuning of magnetic parameters: for example, the addition of Ga to Fe yields magnetostrictive films with large strain coefficients, while CoPt and FePd alloys exhibit strong perpendicular magnetic anisotropy (PMA) vital for high‐density memory. Control of microstructure, from amorphous to well‐ordered L1₀ and L1₁ phases, influences coercivity and damping, affecting switching speeds and energy losses. Recent focus has centred on precise deposition methods—sputtering, epitaxy and electrodeposition—to engineer anisotropy axes, spin polarisation and magnetostrictive response. Optimisation of deposition temperature and post‐annealing further refines texture and grain size, leading to improved soft or hard magnetic performance. Such control underpins emerging applications in low‐power spintronic devices, magnetoelectric sensors and flexible electronics.

Research from Nature Portfolio

Recent studies have demonstrated that equiatomic Co₅₀Pt₅₀ alloy films grown epitaxially on [111] substrates can exhibit robust intrinsic perpendicular magnetic anisotropy without requiring multilayer interfaces. Investigations of the L1₁ and L1₀ ordered phases reveal distinct easy‐axis orientations: the former shows out-of-plane anisotropy while the latter aligns obliquely to the film plane. Measurements of ballistic spin polarisation indicate values approaching 47 per cent, underscoring the potential of CoPt alloys for spin-polarised current injection in superconducting spintronics and magnetic tunnel junctions.

Magnetic Properties of Thin-Film Alloys publication trend

The graph below shows the total number of articles in magnetic properties of thin-film alloys across all publications each year (not limited to Nature Index journals).

Technical terms

Perpendicular magnetic anisotropy (PMA): A condition where magnetic moments preferentially align normal to the film plane, enhancing thermal stability in memory devices.

Magnetostriction: The change in physical dimensions of a material when subjected to a magnetic field, relevant for actuators and sensors.

Coercivity: The magnetic field strength required to reduce the magnetisation of a material to zero, indicative of magnetic hardness or softness.

Spin polarisation: The imbalance between spin-up and spin-down conduction electrons, key to spintronic functionality.

Soft magnetic material: A material with low coercivity and high permeability, suited to high-frequency and low-loss applications.

References

1. Quantitative profilometric measurement of magnetostriction in thin-films. Applied Surface Science (2024).
2. A Co-Sputtering Process Optimization for the Preparation of FeGaB Alloy Magnetostrictive Thin Films. Nanomaterials (2023).
3. Thin film epitaxial [111] Co50Pt50: structure, magnetisation, and spin polarisation. Scientific Reports (2023).
4. The Preparation of High Saturation Magnetization and Low Coercivity Feco Soft Magnetic Thin Films via Controlling the Thickness and Deposition Temperature. Materials (2022).