Nanostructuring of Mn(II)Pc thin films by vacuum deposition in a weak magnetic field

• Published in: Vacuum Vol. 194; p. 110584
• Main Authors: Yunin, Pavel A., Sachkov, Yury I., Travkin, Vlad V., Skorokhodov, Evgeny V., Pakhomov, Georgy L.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2021
• Subjects: Magnetic field; Manganese(II) phthalocyanine; Microstructure; Morphology; Thin films; Vacuum deposition; Whisker crystals; Thin films; Whisker crystals; Morphology; Manganese(II) phthalocyanine; Microstructure; Magnetic field; Vacuum deposition
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2021.110584

Manganese phthalocyanine, Mn(II)Pc, is a disc-like paramagnetic molecule whose unusual electronic structure have been studied for decades. However, no credible results on the direct impact of intrinsic molecular magnetism on the solid state properties of Mn(II)Pc are known. In this work, the Mn(II)Pc films were deposited by thermal vacuum evaporation with and without applying an external static magnetic field with a strength of a few tenths of a Tesla to the growth zone. Evolution of the microstructure of the thus formed films was documented using XRD, SEM, AFM and optical methods. In the field-free conditions, the Mn(II)Pc films deposited on the hot substrate are rather smooth, continuous and strongly textured. Large needle-like crystals (whiskers) grow when magnetic field is turned on, without noticeable correlation with the direction of field lines. However, the density of whiskers per unit area increases with increasing field strength. Possible explanations of the growth mechanism include molecular surface diffusion, adsorption energy lowering and Lorentz force but none of them is yet internally consistent. •Strong effect of magnetic field on vacuum growth of molecular films of paramagnetic manganese phthalocyanine was revealed.•Continuous strongly textured film of manganese phthalocyanine tends to grow without external field.•Whisker crystals sprout from the film when the external magnetic field is applied.•The stronger the external magnetic field, the thicker whisker lawn grows.•No dependence of whiskers orientation on the direction of magnetic field lines is observed.