Giant magnetothermal conductivity and magnetostriction effect in charge ordered Nd$_{0.8}$Na$_{0.2}$MnO$_{3}$ compound

TL;DR

This study investigates the magnetic, thermal, and structural properties of Nd$_{0.8}$Na$_{0.2}$MnO$_{3}$, revealing giant magnetothermal conductivity and magnetostriction effects driven by magnetic field-induced phase transitions.

Contribution

It reports the first observation of giant magnetothermal conductivity and magnetostriction effects in a charge-ordered Nd-based manganite, highlighting strong spin-charge-lattice coupling.

Findings

Magnetic field induces insulator-metal transition.

Giant magnetothermal conductivity observed at low temperatures.

Strong spin-charge-lattice coupling evidenced by irreversibility and similar field/temperature dependence.

Abstract

We present results on resistivity ($\rho$), magnetization ($M$), thermal conductivity ($\kappa$), magnetostriction ($\frac{\Delta L}{L(0)}$) and specific heat ($C_{p}$) of charge-orbital ordered antiferromagnetic Nd$_{0.8}$Na$_{0.2}$MnO$_{3}$ compound. Magnetic field-induced antiferromagnetic/charge-orbital ordered insulating to ferromagnetic metallic transition leads to giant magnetothermal conductivity and magnetostriction effect. The low-temperature irreversibility behavior in $\rho$, $M$, $\kappa$ and $\frac{\Delta L}{L(0)}$ due to field cycling together with striking similarity among the field and temperature dependence of these parameters manifest the presence of strong and complex spin-charge-lattice coupling in this compound. The giant magnetothermal conductivity is attributed mainly to the suppression of phonon scattering due to the destabilization of spin fluctuations and static/dynamic Jahn-Teller distortion by the application of magnetic field.