Large positive room temperature magnetoresistance in nanogranular FeCo–Si–N thin films

• Films with FeCo nanoparticles embedded in amorphous Si–N matrix were prepared.
• A large positive room temperature magnetoresistance ~30% at 50 kOe was obtained.
• Composition, thickness and resistivity dependent MR for FeCo–Si–N films was studied.
• The possible origin of the large positive magnetoresistance was discussed.

A large positive room temperature magnetoresistance (MR) up to ~30% at 50 kOe was obtained in nanogranular FeCo–Si–N thin film prepared by magnetron sputtering. The quasi-linear dependence of MR on the magnetic field is observed for the fields above 20 kOe. The properties of the films depend on both the nonmagnetic component volume and film thickness. To achieve high MR, a proper Si–N content and a critical film thickness are required. The large positive MR may result from the combination of geometric effect as well as spin-dependent scattering. The FeCo–Si–N films with pronounced MR and linear MR-H behavior can be good candidates for future magnetoelectric devices.