Room-temperature spin valve effects in La0.67Sr0.33MnO3/Alq3/Co devices

We report room-temperature spin valve effects in Alq3-based vertical organic spin valve (OSV) devices with direct interfaces between Alq3 and the bottom and top ferromagnetic electrodes. In contrast to conventional OSVs, where the top electrode is directly deposited on top of organic layer, we use indirect deposition method. We find this method can significantly suppress the penetration of Co atoms into Alq3 layer during deposition process, which is commonly found in conventional OSVs. The improved Alq3/Co interface is further confirmed by comparing the magnetic moment of depositing Co onto Alq3 and Si substrates by indirect and direct deposition methods. A penetration length of 12.5 nm in direct deposition Co on top of Alq3 is estimated. And the demonstration of room-temperature spin valve effects indicates the improvement of spin injection efficiency at sharp Alq3/Co interface.