化学气相沉积的有机磁体，钒四氰
Summary
我们提出的基于有机物的亚铁磁钒四氰的合成（Ⅴ[TCNE]，则x〜2）通过低温化学气相沉积（CVD）。这种优化配方产生增加居里温度从400 K至600 K和磁共振性能的显着改善。
Abstract
在有机材料领域中的最新进展已经产生了器件如有机发光二极管（OLED），其具有传统的材料，包括低成本和机械柔韧性没有发现的优点。与此类似，这将是有利的，以扩大利用有机物成高频电子器件和基于自旋的电子器件。这项工作提出的合成方法，薄膜的室温有机亚铁磁的生长，钒四氰（Ⅴ[TCNE]，则x〜2）通过低温化学气相沉积（CVD）。薄膜生长在<60℃下，可容纳各种基材，包括但不限于，硅，玻璃，聚四氟乙烯和柔性基板。的保形沉积，有利于预图案化和三维结构为好。另外，该技术可以得到具有厚度范围从30纳米到几微米的薄膜。最新进展在膜生长的优化产生的膜的品质，如更高的居里温度（600 K），改进的磁性均匀性和窄铁磁谐振线路宽度为各种在自旋电子学和微波电子应用（1.5 g）示出的承诺。
Introduction
有机基铁氧体磁性半导体钒四氰（Ⅴ[TCNE]，则x〜2）表现出室温磁有序和承诺的磁电子应用，如柔软性，低成本的生产，和化学可调谐性的有机材料的优点。以前的研究已经证明，在自旋电子器件，包括杂化有机/无机1,2-和全有机自旋阀3的功能，和作为活性有机/无机半导体异质结构4自旋偏振器。此外，V [TCNE]×〜2展示了承诺列入高频电子产品，由于其极窄的铁磁共振行距5。
有已建立的合成V [TCNE]×〜2月 6日至九日四种不同的方法。 V [TCNE]×〜2首次合成powde经由TCNE和V的反应中的R二氯甲烷（C 6 H 6）6。这些粉末表现出在有机系材料中观察到的第一个室温磁有序。然而，这种材料的粉末形式是极其空气敏感，限制了其在薄膜器件的应用。在2000年，化学气相沉积（CVD）方法建立用于创建V [TCNE]×〜2薄膜7。更多最近的物理气相沉积（PVD）8和分子层沉积（MLD）9也已用于制造薄膜。 PVD法需要超高真空（UHV）系统和两者PVD和MLD方法需要极长的时间来生长膜厚度大于100纳米，而在CVD膜可以很容易地在厚度范围从30纳米到几微米沉积。除了各种可用与CVD法厚度，广泛的研究已经取得了优化的薄膜即一直显示高Quality磁特性包括：窄铁磁共振（FMR）线宽（1.5克），高的居里温度（600 K）和尖锐的磁开关5。
以V [TCNE]×〜2薄膜磁有序通过非常规途径进行。 SQUID磁力测量显示强大的本地磁有序，但由于没有X射线衍射峰和特征的透射型电子显微镜（TEM）10形态揭示缺乏长程结构秩序。然而，扩展X射线吸收精细结构（EXAFS）研究11表明每个钒离子八面体配位与六个不同TCNE分子，表明与2.084（5）埃的钒-氮键长度的稳定的局部结构秩序。磁性源于TCNE的未配对自旋之间的反铁磁性交换耦合–基阴离子，它们分布在整个TCNE –分子，并且在V 2+离子的自旋，导致本地铁磁有序与T C 〜600 K中优化膜5。除了 表现出室温磁有序，V [TCNE]×〜2薄膜半导体为0.5 EV带隙12。值得注意的其他性能包括低于〜150开13,14，反常正磁阻12,15,16，和光诱导磁13,17,18的冷冻温度可能sperimagnetism。
CVD法合成V [TCNE]×〜2薄膜与各种基质的相容因低温（<60℃）和保形沉积。以前的研究显示了V [TCNE]×〜2成功沉积在刚性和柔性基板7。此外，该沉积技术适合于调谐通过前体和改性克owth参数19-22虽然此处所示的协议产生最优化的膜迄今为止，显著进展已取得，因为这种方法的发现改善的一些膜的性质和进一步的增益是可能的。
Protocol
1.合成和前体的制备 [的Et 4 N]的制备[V（CO）6] 23 在氮气手套箱中，切1.88克金属钠到〜40片，并与14.84克蒽的1升三颈圆底烧瓶中混合320毫升无水四氢呋喃（THF）。 注意：这两种金属钠和四氢呋喃是高度易燃的。 在RT搅拌在氮气氛下的溶液4.5小时，直到NAC 14 H 10被形成深蓝色溶液。 冷却该溶液至0℃。 在氮气手套箱?…
Representative Results
第一和最容易的方法，用于确定一个沉积是成功的是做膜的目视检查。这部电影应该会出现暗紫色采用了镜面设计是整个基板均匀。如果在衬底的表面上的斑点，其中有否v [TCNE]×〜2，或者它是在颜色较浅，则这可能是由于溶剂或其它杂质的衬底表面上的存在。此外，该电影应该是不透明的。除非薄膜沉积在只有几分钟的短时间内，半透明膜往往意味着有可能已被与前体的沉积期间…
Discussion
关键参数中V [TCNE]×〜2沉积包括温度，载气流量，压力，和前体的比例。因为化学气相沉积设置不是市售这些参数将需要为每一个系统进行优化。先前的研究由麻等人透露，温度对TCNE前体26的升华速率的影响最大。温度可通过在温度控制器和还通过调整在加热线圈和作为这样的丝间距将需要校准每个系统中设置的值进行修改两者。温度的校准是通过测量反应器内之前?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
这项工作是由美国国家科学基金会批准号DMR-1207243，美国国家科学基金会MRSEC程序支持（DMR-0820414），美国能源部批准号：DE-FG02-03ER46054，以及俄勒冈州立大学，金属材料研究所。作者承认了纳米技术实验室在俄亥俄州立大学，以及CY花王和CY陈技术援助。
Materials
| Equipment | |||
| Nitrogen Glovebox | Vacuum Atmospheres | Omni | steps done in nitrogen glovebox can also be done in an argon glovebox |
| 1 L three-neck round bottom flask | Corning | 4965A-1L | |
| 500 mL round bottom flask | Sigma Aldrich | 64678 | |
| Turbo vacuum pumping station | Agilent Varian | G8701A-011-037 | |
| Glass Stopcock | Kontes | 185000-2440 | |
| Glass two way connecting tube | Corning | 8940-24 | Corning Pyrex(R) 105 degree Angled Tube Adapter with Two-Way 24/40 Standard Taper Joint |
| Coldfinger | Custom part made by OSU chemistry glass shop | ||
| Argon Glovebox | Vacuum Atmospheres | Nexus I | |
| Hot plate stirrer | Corning | 6795 | |
| Thermoeletric cooler | Advanced Thermoelectric | TCP-50 | |
| Temperature controller | Advanced Thermoelectric | TLZ10 | for TE cooler |
| Power supply | Advanced Thermoelectric | PS-145W-12V | for TE cooler and temperature controller |
| Temperature controller | J-Kem Scientific | Model 150 | For heating coil |
| Heating wire | Pelican Wire Company | Nichrome 60 | |
| Custom glassware pieces | Made by OSU Chemistry glass shop | ||
| Vacuum pump | BOC Edwards | XDS-5 | Connected to the CVD set-up |
| Flow meter | Gilmont | GF-2260 | |
| Micrometer valve | Gilmont | 7300 | Controls flow of argon over TCNE |
| Micrometer valve | Gilmont | 7100 | Controls flow of argon over V(CO)6 |
| Tubing | Tygon | R3603 | 1/8 in walls, connected between valves and meter |
| 3-way Stopcock | Nalgene | 6470 | used to adjust the flow rates |
| Pressure gauge | Matheson | 63-4105 | connects to the top of Figure 1 part A |
| SQUID magnetometer | Quantum Design | MPMS-XL | |
| EPR | Bruker | Elexsys | |
| PPMS | Quantum Design | 14T PPMS | |
| Sourcemeter | Keithely | 2400 | |
| Materials | |||
| Sodium metal | Sigma Aldrich | 262714 | |
| Anthracene | Sigma Aldrich | 141062 | |
| Anhydrous tetrahydrofuran | Sigma Aldrich | 186562 | |
| Vanadium(III) chloride tetrahydrofuran complex | Sigma Aldrich | 395382 | |
| Carbon monoxide gas | OSU stores | 98610 | |
| Tetraethylammonium bromide | Sigma Aldrich | 241059 | |
| Phosphoric acid | Sigma Aldrich | 79622 | |
| Methanol | Sigma Aldrich | 14262 | |
| Silcone oil | Sigma Aldrich | 146153 | |
| Copper pellets | Cut from spare copper wire | ||
| Tetracyanoethylene | Sigma Aldrich | T8809 | |
| Glass slides | Gold Seal | 3010 | |
| Activated Charcoal | Sigma Aldrich | 242276 |
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Cite This Article
Harberts, M., Lu, Y., Yu, H., Epstein, A. J., Johnston-Halperin, E. Chemical Vapor Deposition of an Organic Magnet, Vanadium Tetracyanoethylene. J. Vis. Exp. (101), e52891, doi:10.3791/52891 (2015).