Magnetotransport properties of Co$_{90}$Fe$_{10}$/Cu/Ni$_{80}$Fe$_{20}$ pseudo-spin-valve with out-of-plane tilted magnetic field

The giant magnetoresistance (GMR) effect of a pseudo spin valve made of Co$_{90}$Fe$_{10}$/Cu/Ni$_{80}$Fe$_{20}$ has been investigated, with a magnetic field applied perpendicularly tilted to the sample plane. Without using a pinning layer, the magnetic separation of the free and fixed layers is uniquely achieved by utilizing perpendicular fields due to different anisotropy energies between Ni$_{80}$Fe$_{20\, }$and Co$_{90}$Fe$_{10}$. The magneto-transport measurements are carried out by Van der Pauw method in current-in-plane geometry at room temperature. By tilting the magnetic field at different angles from out-of-plane, the GMR plateau's width can be tuned. A plateau width of about 2000 Oe is observed at tilted angle 0.5$^{o}$, which opens a significantly larger window for high-resistance states comparing with a plateau width of 10 Oe for in-plane fields. With the out-of-plane tilted fields, the orientation of the magnetic moments can be tuned continuously out of the sample plane, and the relative orientation between Ni$_{80}$Fe$_{20}$ and Co$_{90}$Fe$_{10}$ can also be tuned by the tilted angle, enabling us to precisely control the sample's states for current-induced spin dynamics study that is very difficult in the case of in-plane applied magnetic fields.