Antiferromagnetic Phase Transition in Four-Layered High-$T_{\text{c}}$ Superconductors Ba2Ca3Cu4O8(FyO1-y)2 with $T_{\text{c}}=55--102$ K: 63Cu- and 19F-NMR Studies

概要

論文の詳細を見る
We report on the magnetic characteristics of four-layered high-$T_{\text{c}}$ superconductors Ba2Ca3Cu4O8(FyO1-y)2 with apical fluorine through 63Cu- and 19F-NMR measurements. The substitution of oxygen for fluorine at the apical site increases carrier density ($N_{\text{h}}$) and $T_{\text{c}}$ from 55 up to 102 K. The NMR measurements reveal that antiferromagnetic order, which can uniformly coexist with superconductivity, exists up to $N_{\text{h}} \simeq 0.15$, which is somewhat smaller than $N_{\text{h}} \simeq 0.17$, the quantum critical point (QCP) for five-layered compounds. The fact that the QCP for the four-layered compounds moves to a region of lower carrier density than for five-layered ones ensures that a decrease in the number of CuO2 layers makes an interlayer magnetic coupling weaker.
Physical Society of Japanの論文
2009-06-15