  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.
