Magnetic reversal in ion-irradiated FePt thin films

A Mougin (1) , J Ferré , O Plantevin , H Cruguel , F Fortuna , H Bernas (1) , A Marty , C Beigné , Yves Samson

1 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information

Previous work on ion irradiation control of FePt thin films magnetic anisotropy is extended to ultrathin films (2-10nm). The effects of 30keV He ion irradiation on the magnetic properties are explored as a function of ion fluence and film thickness. Depending on their growth conditions, the thinnest films exhibit different magnetic properties. Although this affects their final magnetic behaviour, we show that after irradiation at 300 @BULLET C the easy magnetization axis may rotate entirely from inplane to out-of-plane at very low fluences, e.g. 2×10 13 He + /cm 2 on 5 nm thick film. This demonstrates the extreme sensitivity of the magnetic anisotropy to ion-induced local L1 0 ordering. Under these conditions, ultrathin films may exhibit perfectly square hysteresis loops with 100% remnant magnetization and low coercivity.

Mots clés: Physical Sciences

A Mougin, J Ferré, O Plantevin, H Cruguel, F Fortuna, et al.. Magnetic reversal in ion-irradiated FePt thin films. Journal of Physics D: Applied Physics, 2010, 43 (36), pp.365002. ⟨10.1088/0022-3727/43/36/365002⟩. ⟨hal-00569693⟩