Magnetic Anisotropy and Electrical Property Of CoZrTaB Thin Films Deposited by Oblique Sputtering

Abstract

Soft magnetic materials have been studied extensively in the recent years due to their applications in micro-transformers, micro-inductors, spin dependent memories etc. The unique features of these materials are the high frequency operability and high magnetic anisotropy. High uniaxial anisotropy is one of the most important properties for these materials. There are many methods to achieve high anisotropy field (Hk) which include sputtering with presence of magnetic field, exchange bias and oblique angle sputtering without the presence of the magnetic field, etc. There are multiple ways to increase the ferromagnetic resonance frequency which is proportional to coercivity Hk and magnetic saturation Ms. The ferromagnetic resonance depends on softness of the magnetic material to the applied field. With a highly soft magnetic material, one can operate the devices made out of these films at giga hertz regions without loss of efficiency. of the magnetic films is also highly desirable for many applications, such as power conversion and radio frequency (RF) devices operating at high frequencies. 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 method, 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 degree, there is clear magnetic anisotropy observed. Scanning electron microscopy imaging of the cross-section views of such 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.