Field Induced Magnonic Liquid in the 3D Spin Dimerized Antiferromagnet Sr3Cr2O8

We report on ultrasound and magnetization studies in three dimensional, spin dimerized Sr3Cr2O8 as a function of temperature and external magnetic field up to 61 T. It is well established [Phys. Rev. Lett. 103, 207203 2009 ] that this system exhibits a magnonic superfluid phase between 30 and 60 T and below 8 K. By mapping ultrasound and magnetization anomalies as a function of magnetic field and temperature we establish that this superfluid phase is embedded in a domelike phase regime of a high temperature magnonic liquid extending up to 18 K. Compared to thermodynamic results, our study indicates that the magnonic liquid could be characterized by an Ising like order but has lost the coherence of the transverse component