论文标题
旋转中的准二维磁性 - $ \ frac {1} {2} $方格晶格化合物cu [c $ _6 $ _6 $ h $ _2 $（coo）$ _ 4 $ _ 4 $] [H $ _3 $ n-（ch $ _2 $ _2 $）
Quasi two-dimensional magnetism in spin-$\frac{1}{2}$ square lattice compound Cu[C$_6$H$_2$(COO)$_4$][H$_3$N-(CH$_2$)$_2$-NH$_3$]$\cdot$3H$_2$O
论文作者
论文摘要
我们报告了准二维$ s = 1/2 $量子磁铁Cu [C $ _6 $ _6 $ h $ _2 $（coo）$ _ 4 $] [H $ _3 $ n-（ch $ _2 $ _ 2 $ _ 2 $ -NH $ _3 $ _3 $ _ 3 $ _ 3 $ \ cd 3 $ o）。发现它可以在空间群体$ c2/m $的单斜结构中结晶。 CUO $ _4 $ PLAQUETTES通过[C $ _6 $ H $ _2 $（COO）$ _ 4 $ _ 4 $] $^{4-} $（pyromellitic Acid）的阴离子连接到$ ab $平面的二维框架。 [h $ _3 $ n-（ch $ _2 $）$ _ 2 $ -nh $ _3 $] $^{2+} $$ \ cdot $ 3H $ _2 $ o组位于层之间，并通过氢（H ... O）债券提供弱的层间连接。 $ s = 1/2 $挫折的方格（$ j_1-j_2 $）型号与温度相关的磁敏感性有很好的描述沮丧的矩形晶格（$ j_ {1a，b} -j_2 $）模型几乎证实了几乎同型最近的neighbour互动（$ j _ {\ rm 1a}/k _ {\ rm b} \ rm b} \ rm b} \ simeq 5.31 $ k and $ j _ _ { 5.38 $ k）在$ ab $ - 平面和$ j_2/k _ {\ rm b} \ simeq-0.24 $ k中。此外，在$ t = 1.9 $ k时的等温磁化也可以通过非效率的Square lattice型号用$ j_1/k _ rm b b的$ j_1/k. rm b b sime进行了很好的描述。 $ j_2/j_1 $比率，该化合物可以放置在$ j_1 -j_1 -j_2 $相图的néel反铁磁状态中。未检测到磁性长阶的签名降至2 k。
We report the crystal growth and structural and magnetic properties of quasi two-dimensional $S=1/2$ quantum magnet Cu[C$_6$H$_2$(COO)$_4$][H$_3$N-(CH$_2$)$_2$-NH$_3$]$\cdot$3H$_2$O. It is found to crystallize in a monoclinic structure with space group $C2/m$. The CuO$_4$ plaquettes are connected into a two-dimensional framework in the $ab$-plane through the anions of [C$_6$H$_2$(COO)$_4$]$^{4-}$ (pyromellitic acid). The [H$_3$N-(CH$_2$)$_2$-NH$_3$]$^{2+}$$\cdot$3H$_2$O groups are located between the layers and provide a weak interlayer connection via hydrogen (H...O) bonds. The temperature dependent magnetic susceptibility is well described by $S=1/2$ frustrated square lattice ($J_1-J_2$) model with nearest-neighbor interaction $J_1/k_{\rm B} \simeq 5.35$ K and next-nearest-neighbor interaction $J_2/k_{\rm B} \simeq -0.01$ K. Even, our analysis using frustrated rectangular lattice ($J_{1a,b}-J_2$) model confirms almost isotropic nearest-neighbour interactions ($J_{\rm 1a}/k_{\rm B} \simeq 5.31$ K and $J_{\rm 1b}/k_{\rm B} \simeq 5.38$ K) in the $ab$-plane and $J_2/k_{\rm B}\simeq-0.24$ K. Further, the isothermal magnetization at $T=1.9$ K is also well described by a non-frustrated square lattice model with $J_1/k_{\rm B} \simeq 5.2$ K. Based on the $J_2/J_1$ ratio, the compound can be placed in the Néel antiferromagnetic state of the $J_1 - J_2$ phase diagram. No signature of magnetic long-range-order was detected down to 2 K.
