Tuning magnetic coupling in Sr2IrO4 thin films with epitaxial strain

Area of Science:

• Condensed matter physics
• Materials science
• Magnetism

Background:

• Sr2IrO4 is a correlated iridate with potential applications in spintronics.
• Epitaxial strain is a key parameter for tuning material properties.
• Understanding magnetic anisotropy is crucial for device design.

Purpose of the Study:

• To investigate the effects of epitaxial strain on the magnetic properties of Sr2IrO4 thin films.
• To explore the relationship between strain, magnetic correlations, and magnetic ordering.
• To elucidate the microscopic mechanisms behind strain-induced magnetic changes.

Main Methods:

• X-ray resonant magnetic scattering (XRMS) studies.
• Resonant inelastic x-ray scattering (RIXS) studies.
• Epitaxial thin film growth on SrTiO3 and (LaAlO3)0.3(Sr2AlTaO6)0.7 substrates.
• Quantum chemical calculations.

Main Results:

• Films grown under tensile and compressive strain showed anisotropic magnetic correlations.
• In-plane magnetic correlation lengths were significantly longer than out-of-plane.
• Compressive strain suppressed, while tensile strain enhanced, the magnetic ordering temperature (TN).
• Strain modulated the energy of zone-boundary magnons.

Conclusions:

• Epitaxial strain profoundly influences the magnetic anisotropy and ordering temperature of Sr2IrO4.
• Strain-induced changes in bond lengths are responsible for tuning magnetic energy scales.
• These findings offer insights into strain engineering of magnetic properties in iridates.