ÖPG-CMD Joint Meeting 2026

P072 - Cryogenic Focused Ion Beam for the study of anisotropy in the magnetotransport properties of bismuth

Sep 23, 2026, 1:30 PM

1h

RESOWI B+F (University of Graz)

1) Poster M30 - Focused Beam Technologies for Functional Nanodevices Poster session

Speaker

Amaia Sáenz-Hernández (Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza)

Description

The study of anisotropic magnetotransport in quantum materials is of significant interest, although sample preparation remains challenging[1]. Focused ion beam (FIB) has become one of the most widely used techniques for microcrystal device fabrication, however, it is typically combined with other techniques, frequently involving the use of chemical resists[2].
Our research group has developed an in situ fabrication method using FIB exclusively, allowing the study of anisotropic magnetotransport in microscale single crystals that cannot be synthesized into thin films. Two types of devices are fabricated: Horizontal (H), where current flows perpendicular to both the crystallographic c-axis and magnetic field, and Vertical (V), with current parallel to the c-axis and perpendicular to the field (see Figure)[3].
We present magnetotransport measurements on single-crystal bismuth microdevices of both types. As Bi is observed to melt under Ga⁺ FIB irradiation at room temperature, two low-temperature fabrication approaches are implemented: an N₂-based cryo module and a Peltier stage. Devices show the very large magnetoresistance expected from bismuth as well as clear differences in the Shubnikov–de Haas oscillations of the V and H samples[4].

References

[1] M. Ziese, et al., J. Condens. Matter Phys. 2000, 12, 13.
[2] P.J.W. Moll, et al., Condens. Matter Phys. 2018, 9, 147–162.
[3] A. Saenz-Hernandez, et al., MRS Commun. 2025, 15, 414
[4] A.Sáenz-Hernández, et al., Adv. Funct. Mater.. 2026, 20, e17475.