Ta and Ru seed layers effect on the magnetic and optical properties of Ru/Co60Fe20V20 and Ta/Co60Fe20V20 films

The following structures are deposited under the conditions stated: (a) glass/Ru (X nm)/Co60Fe20V20(5 nm) and (b) glass/Ta(Y nm)/Co60Fe20V20(5 nm) at room temperature (RT), where each of X and Y is from 5 nm to 10 nm. The hysteresis loop of glass/Ru (X nm)/Co60Fe20V20(5 nm) and glass/Ta(Y nm)/Co60Fe20V20(5 nm) presents in-plane easy-axis magnetic anisotropy. The saturation magnetization (Ms) of glass/Ru(X nm)/Co60Fe20V20(5 nm) is decreased from 1490 emu/cm3 to 1050 emu/cm3 when the Ru thickness is increased. The maximum Ms of glass/Ru(5 nm)/Co60Fe20V20(5 nm) is about 1490 emu/cm3. The Ms of glass/Ta(Y nm)/Co60Fe20V20(5 nm) displays a concave-up feature. The maximum Ms of glass/Ta(10 nm)/Co60Fe20V20(5 nm) is about 1300 emu/cm3. The Ms varies with the Ru and Ta seed layer thicknesses due to various distances of spin-coupling interaction. In addition, the Hc values have very small ranges from about 1.2 Oe to 3.4 Oe in glass/Ru(X nm)/Co60Fe20V20(5 nm) and 1.0 Oe to 2.6 Oe in glass/Ta(Y nm)/Co60Fe20V20(5 nm), suggesting that the magnetic characteristic is soft magnetism owing to a low Hc and high Ms. The transmittance percentage (%) of glass/Ru(X nm)/Co60Fe20V20(5 nm) and glass/Ta(Y nm)/Co60Fe20V20(5 nm) is decreased from 16.5% to 7% and decreased from 16% to 12%, respectively, as the Ru and Ta thicknesses change from 5 nm to 10 nm, because a greater thickness and interface effect can inhibit the transfer of photon signals through the film, causing low transmittance. According to magnetic and optical performance, the optimal seed layer thicknesses of glass/Ru(X nm)/Co60Fe20V20(5 nm) and glass/Ta(Y nm)/Co60Fe20V20(5 nm) are 5 nm and 10 nm, which are suitable for magnetic-optical recording medium applications.