Enhanced Optical Gap in Bi-layered Manganites La${}_{2-2x}$Sr${}_{1+2x}$Mn${}_2$O${}_7$ near $x=0.4$

Myung Whun Kim, H. J. Lee, B. J. Yang +4

We have systematically investigated the optical conductivity spectra of La${}_{2-2x}$Sr${}_{1+2x}$Mn${}_2$O${}_7$ ($0.3⩽x⩽0.5$). We find that just above the magneti…