论文标题
$^{31} $ P NMR研究基于铁的超导体Ba $ _ {0.5} $ sr $ _ {0.5} $ _ {0.5} $ fe $ _ {2} $（AS $ _ {1-x} $ p $ _ {x}}
$^{31}$P NMR studies of an iron-based superconductor Ba$_{0.5}$Sr$_{0.5}$Fe$_{2}$(As$_{1-x}$P$_{x}$)$_{2}$ with $T_\mathrm{c}$ = 29 K
论文作者
论文摘要
我们报告了$^{31} $ p nmr研究，对Ba $ _ {0.5} $ _ {0.5} $ sr $ _ {0.5} $ _ {2} $ _ {2} $（as $ _ {1-x} $ p $ _ {x} $ _ nim^nim^n. 0. 4. （$ t_ \ MATHRM {C} $ = 29 K）在$ t $ = 14 $ - $ 325 k和$ b_ {0} $ = 1和5 t。旋转单线降低到$ t_ \ mathrm {c} $以下。 $^{31} $ p核自旋晶格放松率1/$ t_ {1} $显示出$ a+bt $（$ a $和$ b $的常数）的渐近行为，$ t> $ 100 k，最低为40 k，在40 k时，对$ t_ \ nathrm {c} $ upterturn the the the 40 k。 1/$ t_ {1} $中的$ a $项表示存在二维抗铁磁旋转波动。负$θ$ = $ - $ 15 k的curie-weiss-type抗铁磁性旋转易感性$χ$（$ q $）$ \ propto $ 1/（$ t $+$ $θ$）在1/$ t_ {1} t $的分析中表明在超级尺寸的状态中表明抗fiferromagnetic nountage。讨论是根据与层间相关性的自旋波动的自洽再归一化理论进行的。
We report $^{31}$P NMR studies of an oriented polycrystalline superconductor of Ba$_{0.5}$Sr$_{0.5}$Fe$_{2}$(As$_{1-x}$P$_{x}$)$_{2}$ with $x\sim$ 0.4 ($T_\mathrm{c}$ = 29 K) at $T$ = 14$-$325 K and $B_{0}$ = 1 and 5 T. The $^{31}$P Knight shift $K_{ab}$ at $B_{0}\perp c$ shows a nearly $T$-independent uniform spin susceptibility above $T_\mathrm{c}$ and a spin singlet decrease below $T_\mathrm{c}$. The $^{31}$P nuclear spin-lattice relaxation rate 1/$T_{1}$ shows an asymptotic behavior of $a+bT$ ($a$ and $b$ are constants) at $T >$ 100 K and the minimum at 40 K with an upturn toward $T_\mathrm{c}$. The $a$ term in 1/$T_{1}$ indicates the presence of two-dimensional antiferromagnetic spin fluctuations. The negative $θ$ = $-$15 K of the Curie-Weiss-type antiferromagnetic spin susceptibility $χ$($Q$) $\propto$ 1/($T$+$θ$) in the analysis of 1/$T_{1}T$ suggests antiferromagnetic instability in the superconducting state. Discussions are made from the self-consistent renormalization (SCR) theory for the spin fluctuations with interlayer correlation.
