Magnetic properties of electrochemically prepared crystalline films of Prussian blue-based molecular magnets KjCrIIk[CrIII(CN)6]l · mH2O
Magnetic properties of electrochemically prepared crystalline films of Prussian blue-based molecular magnets KjCrIIk[CrIII(CN)6]l · mH2O
复制标题
电化学制备普鲁士蓝基分子磁体KjCrIIk[CrIII(CN)6]l·mH2O晶体薄膜的磁性能
DOI：
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发表时间：
2013
影响因子：
2.5
通讯作者：
Gisela Schütz
中科院分区：
文献类型：
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作者：
P. Bhatt;S. Yusuf;R. Bhatt;Gisela Schütz
在-0.5 V和-0.9 V两种不同还原电位下，采用电化学方法合成了普鲁士蓝基分子磁体的晶化膜（厚度约为1 μm），分别得到K0.1CrII1.45[CrIII（CN）6] ·mH 2 O（膜1）和K0.8CrII1.1[CrIII（CN）6] ·mH 2 O（膜2）。使用原子力显微镜（AFM），X射线衍射（XRD），红外（IR）光谱，和直流磁化测量的结构和磁性的薄膜进行了研究。使用AFM检查的膜形态，显示在衬底表面上均匀分布的三角形微晶。红外光谱中1，900 - 2，300 cm−1范围内的CrIII-C N-CrII序列的存在证实了普鲁士蓝类似物的形成。XRD结果揭示了薄膜的结晶性质和布拉格峰的相对强度随K+离子的变化的信息。Cr离子通过C <$N配体的交换作用证实了电子从C <$N分子到Cr离子的转移是铁磁性的。薄膜1和薄膜2的高居里温度分别为195 K和215 K。较高的TC值归因于膜2包含更多的K+离子，导致CrIII（C = N）6空位减少和CrII离子的最近邻数目增加。在居里温度以下的零场冷却和场冷却的磁化数据的分支解释在不同的冷却条件下的磁畴的动力学行为和晶格中的水分子空位的存在。
Crystalline films (thickness ∼1 μm) of Prussian blue-based molecular magnets, synthesized using electrochemical method at two different reduction potentials −0.5 and −0.9 V, result into K0.1CrII1.45[CrIII(CN)6] · mH2O (film 1) and K0.8CrII1.1[CrIII(CN)6] · mH2O (film 2), respectively. The structural and magnetic properties of such films are investigated using atomic force microscopy (AFM), X-ray diffraction (XRD), infrared (IR) spectroscopy, and dc magnetization measurements. The film morphology, examined using AFM, shows uniformly distributed triangular crystallites over the substrate surface. The presence of CrIII–C≡N–CrII sequence, in the range of 1,900 to 2,300 cm−1 in IR spectra, confirms formation of Prussian blue analogues. The XRD results reveal information about the crystalline nature of the films and the relative intensities of the Bragg peaks change with the K+ ions. The exchange interaction between Cr ions through C≡N ligand confirms that the electron transfer from C≡N molecule to Cr ions is ferrimagnetic in nature. The high Curie temperatures (TC) are found to be ∼195 and ∼215 K for film 1 and film 2, respectively. The higher value of TC is attributed to the inclusion of more K+ ions for film 2, resulting decreases in the CrIII(C≡N)6 vacancies and increases in the number of nearest neighbors of CrII ions. The branching in the zero field-cooled and field-cooled magnetization data below Curie temperature is explained in terms of kinetic behavior of magnetic domains with different cooling conditions and the presence of water molecule vacancies in the lattice.