LATENT TRACK FORMATION INDUCED BY HIGH ELECTRONIC-ENERGY LOSS IN HEXAFERRITES BAFE12O19, SRFE12019 - A MAGNETIC INVESTIGATION

Irradiation effects induced by 3. 1 GeV xenon ions and 2. 3 GeV molybdenum ions in two hyperfrequency materials, BaFe//1//2O//1//9 and SrFe//1//2O//1//9, have been investigated by means of Mossbauer spectroscopy and vibrating samples magnetometry. In both cases a track mechanism has been considered to explain the induced damage rate, showing that SrFe//1//2O//1//9 is less sensitive than BaFe//1//2O//1//9 to high energy heavy ion irradiation. For a fluence lower than 7 multiplied by 10**1**1 Xe cm** minus **2 it is shown that the 4f//1 plus 4f//2 sites of the structure are more affected by irradiation than 12k sites. Above 7 multiplied by 10**1**1 a wide distribution of the magnetic hyperfine field has been necessary to fit the Mossbauer data. It could be related to a transition zone separating the amorphous core of the tracks from the unperturbed matrix.