Physical properties of liquid oxygen under ultrahigh magnetic fields

TL;DR

This study investigates how ultrahigh magnetic fields affect liquid oxygen's acoustic properties, revealing significant attenuation linked to local-structure fluctuations and exploring the potential for a magnetic-field-induced liquid-liquid transition.

Contribution

It provides new experimental data on liquid oxygen's behavior under magnetic fields up to 180 T, challenging previous claims of a liquid-liquid transition.

Findings

Sound velocity decreases monotonically with magnetic field.

Sound attenuation increases significantly, indicating local fluctuations.

No evidence of a liquid-liquid transition up to 180 T.

Abstract

We studied the acoustic properties of liquid oxygen up to 90 T by means of ultrasound measurements. We observed a monotonic decrease of the sound velocity and an asymptotic increase of the sound attenuation when applying magnetic fields. The unusual attenuation, twenty times as large as the zero-field value, suggests strong fluctuations of the local molecular arrangement. We point out that the observed fluctuations are related to a liquid-liquid transition or crossover, from a small-magnetization to a large-magnetization liquid, which is characterized by a local-structure rearrangement. To investigate higher-field properties of liquid oxygen, we performed single-turn-coil experiments up to 180 T by means of the acoustic, dilatometric, magnetic, and optical techniques. We observed only monotonic changes of these properties, reflecting the absence of the proposed liquid-liquid transition in our experimental conditions.