2024/05/09 by Seung Gyo Jeong, Jeong, Seung Gyo, In Hyeok Choi +26 · 10 citations
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Magnetic properties of thin films #Materials Science (cond-mat.mtrl-sci) #Multiferroics and related materials #Other Condensed Matter (cond-mat.other)
paper · pdf · doi:10.48550/arxiv.2405.05838
openalex publication_date 2024/05/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Altermagnetism refers to a wide class of magnetic orders featuring magnetic sublattices with opposite spins related by rotational symmetries, resulting in non-trivial spin splitting and magnetic multipoles. However, the direct observation of the altermagnetic order parameter remains elusive. Here, by combining theoretical analysis, electrical transport, X-ray and optical spectroscopies, we establish a phase diagram in hybrid molecular beam epitaxy-grown RuO2/TiO2 (110) films, mapping symmetries along with altermagnetic/electronic/structural phase transitions as functions of film thickness and temperature. This features a novel altermagnetic metallic polar phase in epitaxially-strained 2 nm films, extending the concept of multiferroicity to altermagnets. Such a clear signature of a magnetic phase transition at ~500 K is observed exclusively in ultrathin strained films, unlike in bulk RuO2 single crystals. These results demonstrate the potential of epitaxial heterostructure design to induce altermagnetism, paving the way for emergent novel phases with multifunctional properties.