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Magneto-optical Kerr effect measurements under bipolar pulsed magnetic fields

Soichiro Yamane, Sota Nakamura, Atsutoshi Ikeda, Kosuke Noda, Akihiko Ikeda, Shingo Yonezawa

TL;DR

This study extends magneto-optical Kerr effect measurements to bipolar pulsed magnetic fields up to 13.1 T, enabling full hysteresis characterization with a zero-area-loop Sagnac interferometer and phase-resolved lock-in analysis. A Rust-based CLI supports fast processing of large pulsed-field datasets, and a portable generator delivers bipolar fields while a Rogowski sensor provides accurate field readout. Fe3O4 (001) at room temperature shows Kerr angles matching static-field results, validating the approach, while hysteresis loops observed in alnico5, Nd2Fe14B (coated), and Sm2Co17 demonstrate the method's utility for rapid magnetic material characterization. Overall, the work establishes bipolar pulsed-field MOKE as a versatile tool for both fundamental studies and engineering applications in magnetism.

Abstract

The magneto-optical Kerr effect (MOKE) is a powerful probe of magnetism. Its contact-free optical nature makes it potentially well suitable for measurements under pulsed magnetic fields if various difficulties are overcome. In this paper, we report the establishment of MOKE measurements under bipolar pulsed magnetic fields up to 13.1 T. The accuracy of the setup was demonstrated by the excellent agreement with static-field results on the (001) surface of a Fe3O4 single crystal. Furthermore, clear hysteresis loops of various commercial permanent magnets were successfully observed. The capability for rapid characterization of hysteretic properties highlights the versatility of our pulsed-field MOKE setup for both fundamental materials science and engineering applications.

Magneto-optical Kerr effect measurements under bipolar pulsed magnetic fields

TL;DR

This study extends magneto-optical Kerr effect measurements to bipolar pulsed magnetic fields up to 13.1 T, enabling full hysteresis characterization with a zero-area-loop Sagnac interferometer and phase-resolved lock-in analysis. A Rust-based CLI supports fast processing of large pulsed-field datasets, and a portable generator delivers bipolar fields while a Rogowski sensor provides accurate field readout. Fe3O4 (001) at room temperature shows Kerr angles matching static-field results, validating the approach, while hysteresis loops observed in alnico5, Nd2Fe14B (coated), and Sm2Co17 demonstrate the method's utility for rapid magnetic material characterization. Overall, the work establishes bipolar pulsed-field MOKE as a versatile tool for both fundamental studies and engineering applications in magnetism.

Abstract

The magneto-optical Kerr effect (MOKE) is a powerful probe of magnetism. Its contact-free optical nature makes it potentially well suitable for measurements under pulsed magnetic fields if various difficulties are overcome. In this paper, we report the establishment of MOKE measurements under bipolar pulsed magnetic fields up to 13.1 T. The accuracy of the setup was demonstrated by the excellent agreement with static-field results on the (001) surface of a Fe3O4 single crystal. Furthermore, clear hysteresis loops of various commercial permanent magnets were successfully observed. The capability for rapid characterization of hysteretic properties highlights the versatility of our pulsed-field MOKE setup for both fundamental materials science and engineering applications.
Paper Structure (5 sections, 2 figures, 1 table)

This paper contains 5 sections, 2 figures, 1 table.

Table of Contents

  1. Introduction
  2. Experimental methods
  3. Demonstration of bipolar pulsed-field MOKE measurements using Fe3O4
  4. Bipolar pulsed-field MOKE measurements on various permanent magnets
  5. Conclusion

Figures (2)

  • Figure 1: Results of MOKE measurements on the $(001)$ surface of a Fe$_3$O$_4$ single crystal under a bipolar pulsed magnetic field up to 13.1 T at room temperature. Time dependence of (a) the magnetic field and (b) the total magneto-optical (MO) angle. (c) $\theta_{\mathrm{t}}$ as a function of magnetic field. The inset shows a magnified view around zero magnetic field. For all panels, the color of data points indicate the time evolution from the beginning of the pulse, as shown in the colorbar on the right.
  • Figure 2: Results of MOKE measurements on various permanent magnets under bipolar pulsed magnetic fields at room temperature. Hysteresis loops of (a) alnico5, (b) Nd$_2$Fe$_{14}$B with a Ni/Cu/Ni protective coating, and (c) Sm$_2$Co$_{17}$. Because details of the starting trajectories vary depending on the magnetic history, we here plot representative data exhibiting largest hysteresises. We note that the overall hysteresis loop shapes themselves represent the intrinsic and reproducible properties of each magnet.