Controlling Magnetic Properties of EuS-Based Spin Valve Structures on Si(001)

We report on the growth and magnetic characterization of the ferromagnetic insulator Europium Sulfide (EuS) on (001)-oriented Silicon substrates. The influence of the EuS film thickness on the coercive field and Curie temperature was systematically investigated with regard to a potential application of thin EuS films as spin filter tunnel barriers. In a further step, we fabricated EuS/Si(001) spin valve structures with both ferromagnetic Gd and exchange-biased CoO/Co counter electrodes. An independent magnetic switching of the EuS barrier and the ferromagnetic layers was accomplished by eliminating intermediate magnetic exchange couplings. Our results clearly demonstrate the feasibility to employ thin EuS ferromagnetic insulator films as spin filter tunnel barriers on Silicon(001) in spin valve structures for future magnetotransport experiments.