Pressure- and temperature-induced spin-state transition in single-crystallineLa1−xSrxCoO3(x=0.10and 0.33)

Abstract

We report on the temperature dependence of magnetization $(M)$ and resistivity $(\ensuremath{\rho})$ of ${\text{La}}_{1\ensuremath{-}x}{\text{Sr}}_{x}{\text{CoO}}_{3}$ ($x=0.10$ and 0.33) single crystals. For $x=0.10$, the temperature dependence of field-cooled magnetization $({M}_{\text{FC}})$ and zero-field-cooled magnetization $({M}_{\text{ZFC}})$ are similar to that expected for a canonical spin-glass system. The thermal response of ${M}_{\text{ZFC}}$ for $x=0.33$ indicates a glassy ferromagnetic state. We observe that the ferromagnetic transition temperature ${T}_{C}$ decreases and $\ensuremath{\rho}$ increases rapidly with increasing pressure $(P)$ for the metallic sample $(x=0.33)$ while the dependence of $\ensuremath{\rho}$ on $P$ for the insulating sample $(x=0.10)$ is quite complicated; the pressure coefficient of resistivity $(d\ensuremath{\rho}/dT)$ is sensitive to temperature and applied pressure due to the strong interplay between the pressure-induced band broadening and spin-state transition phenomenon. $d\ensuremath{\rho}/dT$ is large and negative at low-pressure and low-temperature regimes while small and positive at high pressures $(Pg5.4\text{ }\text{GPa})$ and high temperatures $(Tg110\text{ }\text{K})$.