Physicists Unlock the Potential of In-Plane Magnetic Fields for Advanced Magnetotransport

By Institute of Science Tokyo December 25, 2024

Collected at: https://scitechdaily.com/physicists-unlock-the-potential-of-in-plane-magnetic-fields-for-advanced-magnetotransport/

In-plane magnetic fields unveil novel Hall effect behaviors in advanced materials, transforming our understanding of electronic transport.

Researchers from the Institute of Science Tokyo have reported that in-plane magnetic fields induce an anomalous Hall effect in EuCd₂Sb₂ films. By investigating how these fields alter the electronic structure, the team uncovered a significant in-plane anomalous Hall effect. This discovery opens new avenues for controlling electronic transport in magnetic fields, with potential applications in magnetic sensors.

The Hall effect, a fundamental phenomenon in material science, occurs when a material carrying an electric current is subjected to a magnetic field, creating a voltage perpendicular to both the current and the field. While the Hall effect has been extensively studied in materials under out-of-plane magnetic fields, the effects of in-plane magnetic fields have received comparatively little attention.

In recent years, in-plane magnetic fields have attracted growing interest due to their potential to unlock new material behaviors, particularly in materials with singular points in their electronic band structures, such as EuCd₂Sb₂.

Against this backdrop, a team of researchers from the Institute of Science Tokyo (Science Tokyo) and the RIKEN Center for Emergent Matter Science (CEMS), led by Associate Professor Masaki Uchida, explored how in-plane magnetic fields induce the anomalous Hall effect in EuCd₂Sb₂ films. Their study, published in Physical Review Letters on December 3, 2024, sheds light on how these fields induce a distinctive change in electronic band structures.

Uchida explains, “Our findings highlight a new way to manipulate the Hall effect in magnetic materials. This opens up exciting possibilities for future technologies that rely on precise magnetic field measurement, such as magnetic sensing.”

Symmetry and Orbital Magnetization

The team’s efforts revealed that in-plane magnetic fields lead to a significantly large anomalous Hall effect in EuCd₂Sb₂ thin films. This effect changes its sign with rotation of the in-plane magnetic field, exhibiting clear three-fold symmetry for rotation of the in-plane magnetic fields.

Furthermore, the study revealed that these effects are linked to an unusual out-of-plane shift of the singular points in electronic band structures. This shift corresponds to the manifestation of orbital magnetization, which is the rotational motion of an electron wave packet, formulated in modern terms as a quantum geometric tensor in solids. This discovery deepens our understanding of how in-plane magnetic fields change the material’s internal structure.

The researchers also discovered that even small adjustments in the angle of the magnetic field could lead to significant variations in the in-plane anomalous Hall effect. This directional dependence further highlights the material’s versatility and its potential for use in technologies that require precise measurement of magnetic fields along specific directions.

Uchida concludes, “The present work not only heralds a breakthrough in experimentally studying orbital magnetization, but also stimulates materials development for future applications, revolutionizing the concept of the Hall effect ‘from out to in’.”

Overall, this study enhances our understanding of how in-plane magnetic fields influence the electronic properties of advanced materials, such as EuCd₂Sb₂, bringing us closer to developing materials with tailored magnetotransport properties for future technologies.

Reference: “In-Plane Anomalous Hall Effect Associated with Orbital Magnetization: Measurements of Low-Carrier Density Films of a Magnetic Weyl Semimetal” by Ayano Nakamura, Shinichi Nishihaya, Hiroaki Ishizuka, Markus Kriener, Yuto Watanabe and Masaki Uchida, 3 December 2024, Physical Review Letters.
DOI: 10.1103/PhysRevLett.133.236602