Enhancement of longitudinal magneto-optical Kerr effect in HfO2/Co/HfO2/Al/silicon thin films

In this paper, the longitudinal magneto-optical Kerr effect (MOKE) properties of the quadrilayer structure HfO2/Co/HfO2/Al/silicon are investigated experimentally and theoretically. The cavity enhancement of HfO2 on the magneto-optical (MO) Kerr response of the quadrilayer has been confirmed. The giant longitudinal Kerr rotation of −1.04° at wavelength of 570 nm is tested when the cap and intermediate HfO2 layer thicknesses are 15 nm and 30 nm, respectively. The longitudinal Kerr rotation reversal in the wavelength range (440–720 nm) is also observed. It is strongly suggested that the enhanced MOKE stems from the optical reflection and interference of the quadrilayer structure.