장소: 제1과학관 31214  e+첨단강의실 

초록:  Recent years witnessed increasing research activity in exploiting carbon-based materials as a spin transporting channel, which introduces a new avenue for device integration and functionality. Molecule/organic-based magnets, that allow chemical tuning of electronic and magnetic properties, are a promising new class of magnetic materials for future spintronics. The advantages of using organic-based magnets as spin polarizers in spintronic applications include, chemical tunability, highly spin-polarized electronic nature, low temperature processing, optical control of magnetism and conductivity, etc

In this talk, I will present realization of an organic-based magnetic/non-magnetic semiconductor as an electron spin polarizer/spin transporting layer in the standard spintronic device geometry [1,2]. The application of organic small molecule films as the spin transporting layer has been studied extensively recently. However, conceptual understanding of how the spins are injected into and transport through these organic semiconductor films was still lacking. With careful study on film thickness, temperature, and bias dependencies, significant differences between tunneling and giant magnetoresistance were resolved [1]. In addition, the room temperature organic-based magnet, V(TCNE)_x was successfully incorporated into the standard magnetic tunnel junction devices in tandem with LSMO(La_2/3Sr_1/3MnO₃) film [2]. The development of a practical methodology for finely-controlled film growth of an organic-based magnet yielding conformal air stable film morphology with magnetic ordering temperature above room temperature and electrical conductivity comparable to that of inorganic semiconductors is essential to enable a wide range of yet to be realized applications of this hybrid material. Here, by using molecular layer deposition (MLD), we demonstrate the fabrication of thin film laminates of V[TCNE: tetracyanoethylene]_x[3]. The new hybrid laminate films we developed exhibit major improvement in surface morphology, magnetic and electrical properties, as well as with respect to air-stability.

[1] Jung-Woo Yoo, H. W. Jang, V.N. Prigodin, C. Kao, C.B. Eom, and A.J. Epstein, Phys. Rev. B 80, 205207 (2009)

[2] Jung-Woo Yoo, C.-Y. Chen, H. W. Jang, C. W. Bark, V. N. Prigodin, C. B. Eom, and A. J. Epstein, Nature Materials 9, 638 (2010).

[3] Chi-Yueh Kao, Jung-Woo Yoo, Yong Min, and Arthur J. Epstein, ACS Appl. Mater. & Inter. 4, 137 (2012)