Study of In-plane Anisotropy and Domain Structure of (Co/Ni) Multilayer Thin Films Using Longitudinal MOKE

Magnetic thin films with rapid magnetization switching are essential for devices that operate at high frequencies while consuming minimal energy. Here, Cu2nm/[Co0.4nm/Ni0.6nm]x10/Ta3nm thin film was deposited on silicon substrate by dc magnetron sputtering. Its structural and morphological characterization, magnetic properties, and switching behaviours were investigated using XRD, SEM, SQUID, and longitudinal MOKE, respectively. XRD confirms the formation of Co and Ni phases. The longitudinal magneto-optical Kerr effect (L-MOKE) hysteresis study using various azimuthal angles and simultaneous domain imaging indicates rapid magnetization switching with formation of flame-like domain structures. It has easy axis along the in-plane direction (along 0° and 180°). The magnetization switching along positive magnetization direction (0° easy axis) takes place at a very small field of ~10 Oe, compared to its switching along the negative direction (180° easy axis), with a switching field of 8 Oe. Such small switching fields are required for devices which demand quick magnetization switching with low energy consumption, thus making the Co/Ni thin multilayers film a promising contender for a variety of applications, including spintronics devices such as magnetoresistive random access memory (MRAM), magnetic tunnel junction (MTJ), magnetic sensors, and many more.