Synthesis and pressure and field-dependent magnetic properties of the kagome-bilayer spin liquid Ca10Cr7O28

Abstract

We report the synthesis of polycrystalline samples of the recently discovered spin-liquid material ${\mathrm{Ca}}_{10}{\mathrm{Cr}}_{7}{\mathrm{O}}_{28}$ and present measurements of the ambient and high pressure magnetic susceptibility $\ensuremath{\chi}$ versus temperature $T$, magnetization $M$ versus magnetic field $H$ at various $T$, and heat capacity $C$ versus $T$ at various $H$. The ambient pressure magnetic measurements indicate the presence of both ferromagnetic and antiferromagnetic exchange interactions with dominant ferromagnetic interactions and with the largest magnetic energy scale $\ensuremath{\sim}10$ K. The $\ensuremath{\chi}(T)$ measurements under externally applied pressure of up to $P\ensuremath{\approx}1$ GPa indicate the robust nature of the spin-liquid state despite relative increase in the ferromagnetic exchanges. $C(T)$ shows a broad anomaly at $T\ensuremath{\approx}2.4$ K which moves to higher temperatures in a magnetic field. The evolution of the low temperature $C(T,H)$ and the magnetic entropy is consistent with frustrated magnetism in ${\mathrm{Ca}}_{10}{\mathrm{Cr}}_{7}{\mathrm{O}}_{28}$.