Spin resonances in amorphous alloy films

Abstract

Spin resonance studies have been done on a series of amorphous thin films of Y‐Co, Zr‐Co, La‐Fe, Zr‐Fe and Lu‐Fe alloys prepared by co‐evaporation onto room temperature substrates. Y‐Co alloys behave in accord with static magnetic measurements. In Y₂₉Co₇₁ and Y₂₀Co₈₀ the exchange stiffness has been determined to be 0.6×10⁻⁶ and 0.4×10⁻⁶ erg/cm, respectively. Zr‐Co alloys, especially with high Co concentration show highly unexpected behavior by exhibiting several rather narrow resonances. The RE‐Fe alloys are also anomalous in that they give ferromagnetic resonances at 300 K while static measurements fail to show any evidence for long range order.