Low-temperature heat conduction in the Metal-Organic Framework Perovskite [C(NH$_2$)$_3$]Ni(HCOO)$_3$

We report thermal conductivity ($\kappa$) measurements on single crystals of the metal-organic framework perovskite compound [C(NH$_2$)$_3$]Ni(HCOO)$_3$ in the temperature range 5K~$\le T\le$~300K. Measurements with heat flow along different crystallographic directions and under applied electric field will be presented and compared to $\kappa$ measurements on the closely related compounds$^a$ [C(NH$_2$)$_3$]X(HCOO)$_3$ (X=Zn, Cu).Thermal hysteresis, observed in the range 80K~$\leq T\le$~300K, will also be discussed.
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$^a$ D. Shukla {\it et al.}, Appl. Phys. Lett. {\bf 114}, 081907 (2019).