Photovoltaic Effect on Molecule Coupled Ferromagnetic Films of a Magnetic Tunnel Junction

Pawan Tyagi

Published 2011-12-08, updated 2019-08-24Version 2

Economical solar energy conversion to electricity can be boosted by the discovery of fundamentally new photovoltaic mechanism, and a suitable system to realize it with commonly available materials like iron (Fe) and nickel (Ni). This paper reports the observation of photovoltaic effect on a molecular spintronics device, composed of magnetic tunnel junction (MTJ) and organometallic molecular clusters (OMCs). A prefabricated MTJ with exposed side edges, after enabling the bridging of OMC channels between its two ferromagnetic films, exhibited following phenomenon (i) dramatic increase in exchange coupling, (ii) 3-6 orders current suppression and (iii) photovoltaic effect. This paper focuses on the photovoltaic effect. Control experiments on isolated ferromagnetic films suggested that OMCs neither affected the magnetic properties nor produced any photovoltaic effect; photovoltaic effect was only observed on the ferromagnetic films serving as magnetic electrodes in a MTJ. Present paper invites further investigation of the similar photovoltaic effect on other combinations of MTJs and promising magnetic molecules, like single molecular magnets, organometallic clusters and porphyrins. This research can lead to mass producible and economical spin photovoltaic devices.