Quantum phase of the chromium spinel oxide <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>HgCr</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math> in high magnetic fields
Shojiro Kimura, Shusaku Imajo, Masaki Gen, Tsutomu Momoi, Masayuki Hagiwara, Hiroaki Ueda, Yoshimitsu Kohama
Abstract
In this study, we have performed the magnetocaloric effect and the specific heat measurements of chromium spinel oxide $\mathrm{Hg}{\mathrm{Cr}}_{2}{\mathrm{O}}_{4}$, wherein the magnetic ${\mathrm{Cr}}^{3+}$ ions form a highly frustrated pyrochlore lattice with significant spin-lattice coupling. In addition to the known magnetic-field-induced phases, our thermodynamic measurements detect a quantum phase just before the saturation of the magnetization, which has not been expected from the classical theories of the pyrochlore lattice antiferromagnet with spin-lattice coupling. Based on recent theoretical model calculation, we discuss the possibility of a spin nematic state appearing for this quantum phase.