Giant ΔE effect and magnetomechanical coupling factor in amorphous Fe₈₀P₁₃C₇ribbons

The magnetomechanical coupling factor k, the Young's modulus <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</tex> and the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"></tex> effect as a function of bias field were measured by a mechanical resonance method of amorphous Fe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">80</inf> P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</inf> C <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</inf> ribbons which were annealed at different temperatures in a magnetic field. In the ribbon which was annealed at 350°C for 20 minutes, a remarkably large coupling factor k was found in the bias field 5 Oe to be 0.53, which was almost the same as the value of the high magnetostrictive rare earth-Fe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> . The <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"></tex> effect increased with the increase of the bias field, took a gigantic value 0.8 at about 5 Oe and then decreased monotonically with the increase of the bias field. The <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"></tex> effect is known to correspond to a change in sound velocity, so that the change of the sound velocity was also observed as a function of the frequency from 100kHz to 1MHz in a delay line using the ribbons.