Effect of Temperature on the Ferromagnetic-Resonance Field and Line Width of Epitaxial Fe Thin Films

Abstract

The temperature dependence of the ferromagnetic-resonance field (H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">res</sub> ) and line width (DeltaH) of epitaxial Fe thin films were studied. It is observed that H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">res</sub> increases whereas DeltaH decreases with the increase in temperature. The change in H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">res</sub> is governed by the temperature dependence of the saturation magnetization and the magneto-crystalline anisotropy energy of the film. The present low-temperature investigations of H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">res</sub> obeys the well-known T <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3/2</sup> Bloch law. The resonance line width as a function of temperature shows a transition temperature (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> ) separating two different regimes. This behavior may be associated with the temperature dependence of the anistropy. The H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">res</sub> results are confirmed theoretically by simulating the power absorbed at ferromagnetic resonance by using the Landau-Lifsthiz-Gilbert equation.