Electronic specific heat of (La,Nd) 2− xSr xCu 1− yZn yO 4 up to about 300 K

Abstract

Electronic specific heat coefficients γ of La 1.6− x Nd 0.4Sr x CuO 4 (0.0≦ x≦0.25) and La 1.9Sr 0.1Cu 1− y Zn y O 4 have been extracted over the wide temperature range between 2 and 300 K, by carefully subtracting the phonon specific heat C ph from the total specific heat C. For the former system, the x- and temperature( T)-dependence of γ {≡( C− C ph)/ T} show clear evidence for the existence of the “stripe order” around x∼1/8. Cu-site substitution effects on the behavior of γ of La 1.9Sr 0.1Cu 1− y Zn y O 4 and La 1.48Nd 0.4Sr 0.12Cu 1− y Zn y O 4 indicate that the fluctuating “stripe” suppresses the pseudo gap formation in these systems.