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, Sy-Hwang Liou, David 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 - May 9 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

Fingerprint

Ion bombardment
Ion beams
Magnetic properties
Phase transitions
Irradiation
Giant magnetoresistance
Ions
Heating
Industrial heating
Ferromagnetism
Point defects
Coercive force
Energy transfer
Current density
Annealing
Temperature

ASJC Scopus subject areas

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

Cite this

Lai, C. H., Huang, S. H., Yang, C. H., Chiang, C. C., Liou, S-H., Sellmyer, D. J., ... Yokata, T. (2006). Effects of ion-beam irradiation on the L1 0 phase transformation and their magnetic properties of FePt and PtMn Films. In Materials Research Society Symposium Proceedings (pp. 183-194). (Materials Research Society Symposium Proceedings; Vol. 887).

Effects of ion-beam irradiation on the L1 0 phase transformation and their magnetic properties of FePt and PtMn Films. / Lai, Chih Huang; Huang, Sheng Huang; Yang, Cheng Han; Chiang, C. C.; Liou, Sy-Hwang; Sellmyer, David J; Yan, M. L.; Yuan, L.; Yokata, T.

Materials Research Society Symposium Proceedings. 2006. p. 183-194 (Materials Research Society Symposium Proceedings; Vol. 887).

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

Lai, CH, Huang, SH, Yang, CH, Chiang, CC, Liou, S-H, Sellmyer, DJ, Yan, ML, Yuan, L & Yokata, T 2006, Effects of ion-beam irradiation on the L1 0 phase transformation and their magnetic properties of FePt and PtMn Films. in Materials Research Society Symposium Proceedings. Materials Research Society Symposium Proceedings, vol. 887, pp. 183-194, 2005 Materials Research Society Fall Meeting, Boston, MA, United States, 11/28/05.
Lai CH, Huang SH, Yang CH, Chiang CC, Liou S-H, Sellmyer DJ et al. Effects of ion-beam irradiation on the L1 0 phase transformation and their magnetic properties of FePt and PtMn Films. In Materials Research Society Symposium Proceedings. 2006. p. 183-194. (Materials Research Society Symposium Proceedings).
Lai, Chih Huang ; Huang, Sheng Huang ; Yang, Cheng Han ; Chiang, C. C. ; Liou, Sy-Hwang ; Sellmyer, David J ; Yan, M. L. ; Yuan, L. ; Yokata, T. / Effects of ion-beam irradiation on the L1 0 phase transformation and their magnetic properties of FePt and PtMn Films. Materials Research Society Symposium Proceedings. 2006. pp. 183-194 (Materials Research Society Symposium Proceedings).
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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.",
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AB - 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.

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