  Molecular conduction channels between two ferromagnetic electrodes can
produce strong exchange coupling and dramatic effect on the spin transport,
thus enabling the realization of novel logic and memory devices. However,
fabrication of molecular spintronics devices is extremely challenging and
inhibits the insightful experimental studies. Recently, we produced Multilayer
Edge Molecular Spintronics Devices (MEMSDs) by bridging the organometallic
molecular clusters (OMCs) across a ~2 nm thick insulator of a magnetic tunnel
junction (MTJ), along its exposed side edges. These MEMSDs exhibited
unprecedented increase in exchange coupling between ferromagnetic films and
dramatic changes in the spin transport. This paper focuses on the dramatic
current suppression phenomenon exhibited by MEMSDs at room temperature. In the
event of current suppression, the effective MEMESDs' current reduced by as much
as six orders in magnitude as compared to the leakage current level of a MTJ
test bed. In the suppressed current state, MEMSD's transport could be affected
by the temperature, light radiation, and magnetic field. In the suppressed
current state MEMSD also showed photovoltaic effect. This study motivates the
investigation of MEMSDs involving other combinations of MTJs and promising
magnetic molecules like single molecular magnets and porphyrin. Observation of
current suppression on similar systems will unequivocally establish the utility
of MEMSD approach.
