Magnetic anisotropy and electrical property of CoZrTaB thin films deposited by oblique sputtering

Soft magnetic materials have been studied extensively in recent years due to their applications in micro-transformers, micro-inductors, spin dependent memories etc. Achieving high uniaxial anisotropy is one of the most important properties for these materials. Oblique angle sputtering without the presence of the magnetic field enables the ease thus lower cost of the adoption of magnetic materials in applications. With a highly soft magnetic material, one can operate the devices made out of these films at giga hertz regions without significant loss of efficiency thus desirable for applications such as power conversion and radio frequency (RF) devices. This work focuses on analyzing different growth conditions of thin films of CoZrTaB and the resulting magnetic and electrical properties of the films. Thin films are grown by oblique-angle sputtering, where the sputtering gun forms an angle with respect to the sample substrate normal, ranging from 0 to 75 degrees. External magnetic field normally applied in order to form magnetic anisotropy is not used during film sputtering process. Using vibrating sample magnetometer, it was observed that films resulting from small oblique angles have no clear magnetic anisotropy developed; whereas in samples deposited at large angles close to 60°, there is clear magnetic anisotropy observed. Scanning electron microscopy imaging of the cross-section of film suggests the formation of tilted columns, which is likely to be the reason for magnetic anisotropy. Resistivity of the films was measured systematically and found to increase as the magnitude of oblique angle during sputtering increased.