Rotational Grüneisen ratio: a probe for quantum criticality in anisotropic systems

Abstract

The Grüneisen ratio $\Gamma$ and its magnetic analog, the magnetic Grüneisen ratio ${\Gamma }_H$, are powerful probes to study the nature of quantum phase transitions. Here, we propose a Grüneisen parameter, the rotational Grüneisen ratio ${\Gamma }_{\varphi }$, by introducing the orientation of the external field as a control parameter. We investigate ${\Gamma }_{\varphi }$ of the highly anisotropic paramagnets CeRhSn and CeIrSn by measuring the rotational magnetocaloric effect in a wide range of temperatures and magnetic fields. We find that the ${\Gamma }_{\varphi }$ data of both compounds are scaled by using the same critical exponents and the field-invariant critical field angle. Remarkably, the scaling function for the ${\Gamma }_{\varphi }$ data reveals the presence of highly anisotropic quantum criticality that develops as a function of the easy-axis component of the magnetic field from the quantum critical line. This paper provides a thermodynamic approach to detect and identify magnetic quantum criticality in highly anisotropic systems.

6 pages, 3 figures (main text) + 12 pages, 10 figures (Supplemental Material)

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Cited by in corpus (1)

• Probing magnetic-field-induced multipolar ordering through field-angle-resolved magnetostriction and thermal expansion in PrIr${}_2$Zn${}_{20}$