Spin-State Transition and Metal-Insulator Transition in La$_{1-x}$Eu$_x$CoO$_3$}

J. Baier; S. Jodlauk; M. Kriener; A. Reichl; C. Zobel; H. Kierspel; A. Freimuth; T. Lorenz

doi:10.1103/PhysRevB.71.014443

paper

Spin-State Transition and Metal-Insulator Transition in La $_{1 - x}$ Eu $_{x}$ CoO $_{3}$ }

arXiv:cond-mat/0405680 · doi:10.1103/PhysRevB.71.014443

Abstract

We present a study of the structure, the electric resistivity, the magnetic susceptibility, and the thermal expansion of La $_{1 - x}$ Eu $_{x}$ CoO $_{3}$ . LaCoO $_{3}$ shows a temperature-induced spin-state transition around 100 K and a metal-insulator transition around 500 K. Partial substitution of La $^{3 +}$ by the smaller Eu $^{3 +}$ causes chemical pressure and leads to a drastic increase of the spin gap from about 190 K in LaCoO $_{3}$ to about 2000 K in EuCoO $_{3}$ , so that the spin-state transition is shifted to much higher temperatures. A combined analysis of thermal expansion and susceptibility gives evidence that the spin-state transition has to be attributed to a population of an intermediate-spin state with orbital order for $x < 0.5$ and without orbital order for larger $x$ . In contrast to the spin-state transition, the metal-insulator transition is shifted only moderately to higher temperatures with increasing Eu content, showing that the metal-insulator transition occurs independently from the spin-state distribution of the Co $^{3 +}$ ions. Around the metal-insulator transition the magnetic susceptibility shows a similar increase for all $x$ and approaches a doping-independent value around 1000 K indicating that well above the metal-insulator transition the same spin state is approached for all $x$ .

arXiv comment10 pages, 6 figures

Spin-State Transition and Metal-Insulator Transition in La $_{1 - x}$ Eu $_{x}$ CoO $_{3}$ }

Abstract

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Cited by in corpus (29)

Spin-State Transition and Metal-Insulator Transition in La1−x​Eux​CoO3​}

Abstract

References in corpus (6)

Cited by in corpus (29)

Spin-State Transition and Metal-Insulator Transition in La $_{1 - x}$ Eu $_{x}$ CoO $_{3}$ }