New Aspects of Microwave Absorption in Ferromagnetic Ni-Mn-Sn Thin Films |
| A. Srinivasana, b, R. Modakb, C. Swapnaa, V.V. Srinivasua
aDepartment of Physics, University of South Africa, Johannesburg 1710, South Africa bDepartment of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, India |
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| Heusler alloy films sputtered on Si (100) substrates from a Ni-Mn-Sn target under identical conditions but vacuum annealed at slightly different ramping rates at 550° (designated as F1 and F2) have nearly equal compositions. Room temperature X-ray diffraction patterns confirmed single phase cubic austenite (L21) structure in both films. The average grain size of the films varied from 14.4 nm (F1) to 11.9 nm (F2) due to the difference in annealing conditions. Microwave absorption spectra of F1 and F2 recorded at 9.44 GHz showed a non-resonant low field signal and a ferromagnetic resonance signal. Angular variation of ferromagnetic resonance signal analyzed using Landau-Lifshitz-Gilbert equation yielded slightly different effective perpendicular magnetic anisotropy but the same Gilbert damping constant for both films. A comparative study of ferromagnetic resonance linewidth of F1 and F2 reveals the sensitivity of the technique to subtle microstructural variations in the films. |
DOI:10.12693/APhysPolA.134.178 topics: Heusler alloy, thin film, magnetic anisotropy, ferromagnetic resonance, Gilbert damping |