Tuneable magnetic patterning of paramagnetic Fe{sub 60}Al{sub 40} (at. %) by consecutive ion irradiation through pre-lithographed shadow masks

Journal Article · Sun May 01 00:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3590158· OSTI ID:21560232

Varea, A; Surinach, S; Baro, M D ^[1]; Menendez, E ^[2]; Montserrat, J; Lora-Tamayo, E ^[3]; Weber, A; Heyderman, L J ^[4]; Deevi, S C ^[5]; Rao, K V ^[6]; Buchanan, K S ^[7]; Nogues, J ^[8]; Sort, J ^[9]

---

1. Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain)
2. Instituut voor Kern- en Stralingsfysica and INPAC, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, BE-3001 Leuven (Belgium)
3. Institut de Microelectronica de Barcelona (IMB-CNM), CSIC, Campus Universitat Autonoma Barcelona, E-08193, Bellaterra (Spain)
4. Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)
5. Research Center, Philip Morris USA, Inc., 4201 Commerce Road, Richmond, Virginia 23234 (United States)
6. Department of Materials Science and Engineering, Royal Institute of Technology, S-10044, Stockholm (Sweden)
7. Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)
8. Institucio Catalana de Recerca i Estudis Avancats (ICREA) and CIN2 (ICN-CSIC) and Universitat Autonoma de Barcelona, Catalan Institute of Nanotechnology, Campus de la UAB, E-08193 Bellaterra (Spain)
9. Institucio Catalana de Recerca i Estudis Avancats (ICREA) and Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain)

Arrays of ferromagnetic circular dots (with diameters ranging from 225 to 420 nm) have been prepared at the surface of atomically ordered paramagnetic Fe{sub 60}Al{sub 40} (at. %) sheets by means of ion irradiation through prelithographed poly(methyl methacrylate) (PMMA) masks. The cumulative effects of consecutive ion irradiation (using Ar{sup +} ions at 1.2 x 10{sup 14} ions/cm{sup 2} with 10, 13, 16, 19 and 22 keV incident energies) on the properties of the patterned dots have been investigated. A progressive increase in the overall magneto-optical Kerr signal is observed for increasingly larger irradiation energies, an effect which is ascribed to accumulation of atomic disorder. Conversely, the coercivity, H{sub C}, shows a maximum after irradiating at 16-19 keV and it decreases for larger irradiation energies. Such a decrease in H{sub C} is ascribed to the formation of vortex states during magnetization reversal, in agreement with results obtained from micromagnetic simulations. At the same time, the PMMA layer, with an initial thickness of 90 nm, becomes progressively thinned during the successive irradiation processes. After irradiation at 22 keV, the remaining PMMA layer is too thin to stop the incoming ions and, consequently, ferromagnetism starts to be generated underneath the nominally masked areas. These experimental results are in agreement with calculations using the Monte-Carlo simulation Stopping Range of Ions in Matter software, which show that for exceedingly thin PMMA layers Ar{sup +} ions can reach the Fe{sub 60}Al{sub 40} layer despite the presence of the mask.

• OSTI ID: 21560232
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 9; Other Information: DOI: 10.1063/1.3590158; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
ALUMINIUM ALLOYS
ARGON IONS
COERCIVE FORCE
COMPUTERIZED SIMULATION
ENERGY LOSSES
FERROMAGNETIC MATERIALS
HYSTERESIS
ION BEAMS
IRON ALLOYS
IRRADIATION
KERR EFFECT
KEV RANGE 10-100
LAYERS
MAGNETIZATION
MAGNETO-OPTICAL EFFECTS
MONTE CARLO METHOD
NANOSTRUCTURES
PARAMAGNETISM
PMMA
STOPPING POWER
ALLOYS
BEAMS
CALCULATION METHODS
CHARGED PARTICLES
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
ENERGY RANGE
ESTERS
IONS
KEV RANGE
LOSSES
MAGNETIC MATERIALS
MAGNETISM
MATERIALS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PHYSICAL PROPERTIES
POLYACRYLATES
POLYMERS
POLYVINYLS
SIMULATION
TRANSITION ELEMENT ALLOYS