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arXiv · 1507.03249

Indirect Spin Exchange Interaction in Substituted Copper Phthalocyanine Crystalline Thin Films

Naveen Rawat·Zhenwen Pan·Cody J. Lamarche·Takahisa Tokumoto·Judy G. Cherian·Anthony Wetherby·Rory Waterman·Randall L. Headrick·Stephen A. McGill·Madalina I. Furis
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Abstract

The origins of indirect spin exchange in crystalline thin films of Copper Octabutoxy Phthalocyanine (Cu-OBPc) are investigated using Magnetic Circular Dichroism (MCD) spectroscopy. These studies are made possible by a solution deposition technique which produces highly ordered films with macroscopic grain sizes suitable for optical studies. For temperatures lower than 2 K, the contribution of a specific state in the valence band manifold originating from the hybridized lone pair in nitrogen orbitals of the Phthalocyanine ring, bears the Brillouin-like signature of an exchange interaction with the localized $\textit{d}$-shell Cu spins. A comprehensive MCD spectral analysis coupled with a molecular field model of a $\sigma\pi-d$ exchange analogous to $\textit{sp-d}$ interactions in Diluted Magnetic Semiconductors (DMS) renders an enhanced Zeeman splitting and a modified $\textit{g}$-factor of -4 for the electrons that mediate the interaction. These studies define an experimental tool for identifying electronic states involved in spin-dependent exchange interactions in organic materials.

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Naveen Rawat, Zhenwen Pan, Cody J. Lamarche, Takahisa Tokumoto, Judy G. Cherian, Anthony Wetherby, Rory Waterman, Randall L. Headrick, Stephen A. McGill, Madalina I. Furis. 2015-07-12. Indirect Spin Exchange Interaction in Substituted Copper Phthalocyanine Crystalline Thin Films. https://arxiv.org/abs/1507.03249

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