Materials such as L10 Fe-based alloys with perpendicular magnetic anisotropy derived from crystal structure have the potential to deliver higher thermal stability of magnetic memory elements compared to materials whose anisotropy is derived from surfaces and interfaces. A number of processing parameters enable control of the quality and texture of L10 FePd; among them are substrate, deposition temperature, pressure, and seed and buffer layer. The angle of inclination between the substrate and the sputtering target can also impact the texture of L10 crystallization of sputtered FePd and magnetic properties of the derived thin films. This letter examines the difference between FePd layers that have been magnetron sputter deposited on Cr(15 nm)/Pt, Ir, or Ru(4 nm)/FePd (8 nm)/Ru(2 nm)/Ta(3 nm) substrate layers at an oblique angle (30° tilt from the sputtering target) versus normal incidence (target facing the substrate). X-ray diffraction, ferromagnetic resonance spectroscopy, and vibrating sample magnetometry were used to compare the degree of L10 order and static and dynamic properties of films deposited under both conditions. The films grown using the oblique orientation exhibit stronger degree of L10 orientation, larger magnetic anisotropy energy, and lower Gilbert damping, on all three buffer layers.
Bibliographical noteFunding Information:
This work was supported in part by the Defense Advanced Research Projects Agency HR001117S0056–FP–02 “Advanced MTJs for computation in and near random access memory” and in part by the National Institute of Standards and Technology. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from the National Science Foundation through the Materials Research Science and Engineering Centers program.
© 2010-2012 IEEE.
- Gilbert damping
- Magnetism in solids
- magnetoresistive random-access memory
- perpendicular magnetic anisotropy