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Pressure-Tuned Collapse of the Mott-Like State in Ca_{n+1}Ru_nO_{3n+1} (n=1,2): Raman Spectroscopic Studies

C. S. Snow·S. L. Cooper·G. Cao·J. E. Crow·H. Fukazawa·S. Nakatsuji·Y. Maeno
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Abstract

We report a Raman scattering study of the pressure-induced collapse of the Mott-like phases of Ca_3Ru_2O_7 (T_N=56 K) and Ca_2RuO_4 (T_N=110 K). The pressure-dependence of the phonon and two-magnon excitations in these materials indicate: (i) a pressure-induced collapse of the antiferromagnetic (AF) insulating phase above P* ~ 55 kbar in Ca_3Ru_2O_7 and P* ~ 5-10 kbar in Ca_2RuO_4, reflecting the importance of Ru-O octahedral distortions in stabilizing the AF insulating phase; and (ii) evidence for persistent AF correlations above the critical pressure of Ca_2RuO_4, suggestive of phase separation involving AF insulator and ferromagnetic metal phases.

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C. S. Snow, S. L. Cooper, G. Cao, J. E. Crow, H. Fukazawa, S. Nakatsuji, Y. Maeno. 2002-08-02. Pressure-Tuned Collapse of the Mott-Like State in Ca_{n+1}Ru_nO_{3n+1} (n=1,2): Raman Spectroscopic Studies. https://doi.org/10.1103/physrevlett.89.226401

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