Magnetic Properties of Heusler Alloys

Heusler alloys are ternary or quaternary intermetallic compounds, typically formulated as X₂YZ or XX′YZ, whose magnetic behaviour can be engineered through their valence electron count, atomic ordering and lattice symmetry. They often exhibit half-metallic ferromagnetism, in which one spin channel is metallic while the opposite is semiconducting, yielding near-100 % spin polarisation at the Fermi level. Many members possess high Curie temperatures, robust ferrimagnetic order or spin-gapless semiconducting states, and some display topological electronic structures and significant magnetocaloric effects. Tetragonal distortions and controlled doping further enable the tuning of magnetocrystalline anisotropy energies, facilitating applications in spin-transfer torque devices, magnetic tunnel junctions and rare-earth-free hard magnets. Advances in density functional theory and combinatorial synthesis have expanded the compositional landscape to include quaternary and inverse Heuslers, revealing strong interrelations between electronic structure, exchange interactions and lattice dynamics. This versatility underpins the global significance of Heusler alloys for next-generation spintronics, energy-efficient refrigeration and environmentally benign magnetic materials.

Research from Nature Portfolio

Recent studies have predicted novel quaternary Heusler compounds with valence electron counts optimised to achieve spin polarisation approaching unity alongside Curie temperatures well above ambient, demonstrating that precise atomic arrangements govern the stability of half-metallic gaps and interatomic exchange parameters. In parallel, investigations into Fe₂TaAl and Fe₂TaGa have employed advanced exchange–correlation functionals and phonon dispersion analysis to confirm that these alloys combine a semiconducting gap in one spin channel with mechanical and dynamical stability, thus identifying new semiconducting Heusler magnets suitable for integration in spintronic architectures.

Magnetic Properties of Heusler Alloys publication trend

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

Technical terms

Heusler alloy: An intermetallic compound with stoichiometry X₂YZ or XX′YZ, where X and Y are transition metals and Z is a main-group element, noted for tunable magnetic and electronic properties.

Half-metallicity: A state in which electrons of one spin orientation exhibit metallic conductivity while those of the opposite spin experience a semiconducting or insulating band gap.

Curie temperature: The critical temperature above which a ferromagnetic or ferrimagnetic material loses its spontaneous magnetisation and becomes paramagnetic.

Slater–Pauling rule: An empirical relationship correlating the total magnetic moment per formula unit of certain alloys to their total number of valence electrons.

Magnetocrystalline anisotropy: The dependence of a material’s magnetic energy on the direction of magnetisation relative to its crystallographic axes, critical for coercivity in permanent magnets.

Ferrimagnetism: A form of magnetic order in which unequal antiparallel magnetic moments on different sublattices result in a nonzero net magnetisation.

References

1. Design Scheme of New Tetragonal Heusler Compounds for Spin‐Transfer Torque Applications and its Experimental Realization. Advanced Materials (2012).
2. Basics and prospective of magnetic Heusler compounds. APL Materials (2015).
3. Elastic properties and stability of Heusler compounds: Cubic Co2YZ compounds with L21 structure. Journal of Applied Physics (2018).
4. Large magnetocrystalline anisotropy in tetragonally distorted Heuslers: a systematic study. Journal of Physics D (2017).
5. New quaternary half-metallic ferromagnets with large Curie temperatures. Scientific Reports (2017).
6. Lattice dynamics, mechanical stability and electronic structure of Fe-based Heusler semiconductors. Scientific Reports (2019).
7. Electronic, Magnetic, Half-Metallic, and Mechanical Properties of a New Equiatomic Quaternary Heusler Compound YRhTiGe: A First-Principles Study. Materials (2018).