arXiv subjects

Kosuke Noda

Publications and source records attributed to Kosuke Noda.

6 recordsLinked to original sources

arXiv2026

Pulse magnet of 10 T for power laser experiments with x-ray free-electron laser diagnostics

The importance of investigating magnetized plasmas/solids in extreme conditions has grown over the last decades, particularly in the field of high energy density physics (HEDP), such as laboratory astrophysics and inertial confinement fusion. However, up to now, the unique capabilities of an X-ray free-electron laser (XFEL), such as high brilliance and low divergence have never been exploited for this type of research. In this paper, we present the first platform developed at SACLA, Japan, that combines a high-power optical laser for generating matter under extreme conditions of pressure and temperature, an XFEL probe, and an external magnetic field. The high current is produced using a 2 kV, 4.8 kJ pulsed power system giving a maximum current of 10 kA which is synchronized with the optical laser and XFEL in a vacuum environment. It flows through a split-pair coil to generate a high magnetic field (10 T at 6 kA) which has 1 cm access every 45$^{\circ}$ in the equatorial plane and 90$^{\circ}$ in the poloidal one. This platform offers new opportunities to study high-energy-density matter in strong magnetic fields, including shock propagation, instability growth, and turbulent plasma dynamics.

physics.plasm-ph↗

arXiv2026

Magneto-optical Kerr effect measurements under bipolar pulsed magnetic fields

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.

cond-mat.str-el↗

arXiv2025

Magneto-optical Kerr-effect measurements under pulsed magnetic fields over 40 T using a compact sample fixture

The magnetic field is one of the most fundamental control parameters in materials science. A pulsed magnetic-field apparatus can generate high magnetic fields that are inaccessible by conventional DC-field magnets. One important issue is that measurement techniques compatible with pulsed fields are rather limited due to short pulse duration and large electromagnetic or mechanical noise originating from field pulses. The magneto-optical Kerr effect (MOKE), the change in the state of light polarization upon reflection from magnetic materials, has the potential to become a powerful tool for investigation of magnetic properties of a wide range of materials including non-transparent materials or thin films in pulsed fields. Nevertheless, since the MOKE response is typically very small, MOKE measurements under pulsed fields are quite challenging. Here, we present a new method to measure polar MOKE under high pulsed magnetic fields of 2-ms pulse width. The keys of this new technique are a ferrule-based compact sample-fiber fixture and a phase-resolved numerical lock-in analysis, combined with the high-resolution optical apparatus based on an all-fiber loop-less Sagnac interferometer. We succeeded in measuring MOKE signals from various ferromagnetic or ferrimagnetic samples above 40 T and down to 77 K, significantly extending the limits of previously reported pulse-field MOKE measurements. Our apparatus is simple enough to be compatible with larger-scale experiments in pulse-field facilities, thus becoming a new promising tool to optically investigate material properties in pulsed fields.

cond-mat.str-el↗

arXiv2025

Vector pulse magnet

The underlying symmetry of the crystal, electronic structure, and magnetic structure manifests itself in the anisotropy of materials' properties, which is a central topic of the present condensed matter research. However, it demands such a considerable effort to fill the explorable space that only a small part has been conquered. We report a vector pulse magnet (VPM) as an alternative experimental technique to control the direction of applied magnetic fields, which may complement the conventional methods with its characteristic features. The VPM combines a conventional pulse magnet and a vector magnet. The VPM can create vector pulsed magnetic fields and swiftly rotating pulsed magnetic fields. As a demonstration, the three-dimensional magnetoresistance measurement of a highly oriented pyrolytic graphite is carried out using the AC four-probe method at 4.5 K and 6 T. The two-dimensional electronic structure of graphite is visualized in the three-dimensional magnetoresistance data. One can uncover the rotational and time-reversal symmetry of materials using a VPM and a variety of measurement techniques.

cond-mat.mtrl-sci↗

arXiv2025

X-ray free-electron laser observation of giant and anisotropic magnetostriction in $\beta$-O$_{2}$ at 110 Tesla

In strong magnetic fields beyond 100 T, the significant Zeeman energy competes with the lattice interactions, where a considerable magnetostriction is expected. However, the microscopic observation of the magnetostriction above 100 T has been hindered due to the short pulse duration of $\mu$-seconds and the coil's destruction. Here, we report the observation of the giant and anisotropic magnetostriction of $\sim 1$ % at 110 T in the spin-controlled crystal, $\beta$-O$_{2}$, by combining the single-shot diffraction of x-ray free-electron laser (XFEL) and the newly developed portable 100 T generator (PINK-02). The very soft and anisotropic response of $\beta$-O$_{2}$ should originate in the competing van der Waals force and exchange interaction, and also the frustration of spin and lattice on the triangular network. The XFEL experiment above 100 T using PINK-02 enables microscopic investigations on materials' properties at high magnetic fields, providing insights into how spins contribute to the stability of crystal structures.

cond-mat.str-el↗

arXiv2024

A concise 40 T pulse magnet for condensed matter experiments

There is a growing interest in using pulsed high magnetic field as a controlling parameter of physical phenomena in various scientific disciplines, such as condensed matter physics, particle physics, plasma physics, chemistry and biological studies. We devised a concise and portable pulsed magnetic field generator that produces a 40 T field with a pulse duration of 2 ms. It is assembled using only off-the-shelf components and a homemade coil that leverages small computers, Raspberry Pi, and Python codes. It allows for straightforward modification for general purposes. As working examples, we show representative applications in condensed matter experiments of magnetoresistance, magnetization, and magnetostriction measurements for graphite, NdNi$_{2}$P$_{2}$, and NdCo$_{2}$P$_{2}$, respectively, with the maximum magnetic field of 41 T and the lowest temperature of 4.2 K.

cond-mat.mtrl-sci↗