Effects of ion-beam irradiation on the L1 0 phase transformation and their magnetic properties of FePt and PtMn Films

Chih Huang Lai, Sheng Huang Huang, Cheng Han Yang, C. C. Chiang, S. H. Liou, D. J. Sellmyer, M. L. Yan, L. Yuan, T. Yokata

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In this paper, we illustrate how to modify the structure and magnetic properties of L1 0 FePt and PtMn films using ion-beam irradiation. Highly ordered L1 0 FePt and PtMn phases were achieved directly by using 2 MeV He-ion irradiation without conventional post-annealing. A high ion-beam current density (∼μA/cm 2) was used to achieve direct beam heating on samples. This irradiation-induced heating process provides efficient microscopic energy transfer and creates excess point defects, which significantly enhances the diffusion and promotes the formation of the ordered L1 0 phase. In-plane coercivity of FePt films greater than 5700 Oe could be obtained after disordered FePt films were irradiated with a He-ion dose of 2.4×10 16 ions/cm2. The direct ordering of FePt took place by using ion-irradiation heating at a temperature as low as 230°C. In PtMn-based spin valves, an L1 0 PtMn phase, a large exchange field and a high giant magnetoresistance (GMR) ratio (11%) were simultaneously obtained by using He-ion irradiation. On the other hand, Ge-ion and O-ion irradiation completely destroyed the ferromagnetism of FePt and the GMR of PtMn-based spin valves, respectively.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium Proceedings
Pages183-194
Number of pages12
StatePublished - 2006
Event2005 Materials Research Society Fall Meeting - Boston, MA, United States
Duration: Nov 28 2005Dec 1 2005

Publication series

NameMaterials Research Society Symposium Proceedings
Volume887
ISSN (Print)0272-9172

Conference

Conference2005 Materials Research Society Fall Meeting
CountryUnited States
CityBoston, MA
Period11/28/0512/1/05

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Fingerprint Dive into the research topics of 'Effects of ion-beam irradiation on the L1 <sub>0</sub> phase transformation and their magnetic properties of FePt and PtMn Films'. Together they form a unique fingerprint.

Cite this