Speaker
Description
$\mu$SR is a powerful technique for probing internal magnetic fields and their dynamic behavior and it has been widely used in the study of magnetic and superconducting materials. However, due to limitations such as the relatively small sample volume, there are very few experimental reports of $\mu$SR under high-pressure conditions exceeding 10 GPa.
To address this challenge, we are developing a new apparatus that enables $\mu$SR measurements under low-temperature and high-pressure conditions, based on a conventional opposed anvil high-pressure equipment. This technique is expected to provide new insights into hydride superconductors, which exhibit superconductivity at near room temperature under high pressure [1].
We fabricated a mock-up of the pressure cell, consisting of a silver mask, a diamond disc, and a Teflon sample, which are aligned along the beam direction. $\mu$SR measurements were conducted at J-PARC MLF S1 by using the surface muon beam. Under the conditions of a 0.3 mm-thick diamond and a Teflon cross-sectional area of 4π mm², we successfully obtained $\mu$SR time spectra exhibiting the characteristic F-$\mu$-F precession signal from the sample. The fraction of muons stopping in Teflon was estimated to be 2.5% of the total, which is considerably smaller than that expected for the beam spot size. Simulation results suggested that the beam was spreading after passing through the collimator.
[1]A. P. Drozdov et al.: Nature, 569 528 (2019)
| fukushima@hpr.stec.es.osaka-u.ac.jp | |
| Funding Agency | KAKENHI Grant Number JP 22H00110 |
| Supervisors Name | K. Shimizu |
| Supervisors Email | shimizu.katsuya.es@osaka-u.ac.jp |
