2011 02/25 Principle Application JST-CREST (Kotsugi Masato)
MRAM High-k ReRAM MRAM CNT ReRAM Li-ion PEEM nm //
Rapid increase of areal density in electro-devices Scanning electron microscope Spatial information (several tens nm) MCDMLD Energy tunability Synchrotron radiation energy tunablity polarity pulse Time resolving We can get these information directly Microscopy + Spectroscopy Seeing knowing PEEM
2007 2007 2010 Prof. Peter Grünberg Prof. Gerhard Ertl Prof. Andre Geim Ferro-mag. Antiferro-mag. 111.8 ev 2 3 1 2 m ntensity (a a.u.) 1ML 2ML 3ML I W. Kuch, M. Kotsugi et al. Nature Materials 5 ( 2006 ) 128 J. Chem. Phys. 98, 9977 (1993) 110.0 111.0 112.0 Start voltage (V) Phys. Rev. B 79 (2009) 125437
SPELEEM @ SPring-8 BL17SU Tool for nanotechnology and related research field(s)
(PEEM) MCP Co 2nd 40µm 1st () σ + σ PEEM
SPELEEM by Elmitec BL scientists: M. Kotsugi and T. Ohkouchi Imaging mode NanoXAFS Sample Hg lamp Objective lens FeO mirror image Real space Elemental mapping Chemical mapping Topology LEED mode Reciprocal space Energy analyzer Beam separator LEED pattern k-space mapping Imaging optics Electron gun FeO LEED Ag3d 5/2 0.4eV 3i imaging i mode 3 light source High spatial resolution Dispersion mode Ag/Si(111) h : 530eV Ag3d 3/2 Local XPS Electronic state
Improvement in lateral resolution of SPELEEM PEEM 200nm Co 80 Pt 20 nano dots Width 50nm Spacing 200nm EB lithography hv = 778.44eV Field of view = 2um STV = 0 V LEEM (low energy electron emission microscopy) 200nm Pb/Cu(111) nano dots FOV=1.86um STV=7.67V Lateral resolution 85nm 22nm Lateral resolution7.6nm
Magnetic domain images of CoPt nanodots Dot width 100nm MFM International Space station (ISS) PEEM 500nm Othello Magnetic domain of 100nm CoPt dot is visible g (close to MFM)
SPring-8 X
Meteorite on PEEM A new application to planetary science
Motivation Iron Meteorite Widmanstatten structure Schematic view of interface region Magnetic recording medium 5mm Mixed crystal composed of α and γ-feni Fine metallographic structure 4.6 billion years to produce Magnetism Large Magnetic anistropy Large coercivity Tetrataenite(L1 0 -FeNi) Significant difference from synthetic FeNi Tetrataenite (L1 0 -Fe 50 Ni 50 ) Specific FeNi phase [111] fcc lamella ( fcc-feni) [110] bcc lamella (bcc-feni) Interface orientation {110} α // {111} γ Naturally fabricated magnetic multilayer Nano-scale analysis Structure Composition Photoelectron emission microscope (PEEM) Magnetic domain
Iron Meteorite () 800 600 γ-feni α-feni 400 α+γ FeNi 3 Fe FeNi 3Ni 200 0 25 50 75 100 Ni(%) [110] bcc [1-10] bcc
Local structure analysis by PEEM(NanoXAFS) 50m Ni K 10m αbcc structureni=5at% γfcc structureni>25at% Rapid increasing of Ni composition as close to theinterface L1 0 -FeNi phase is condensed at the interface region 5m
Magnetic domain imaging by MCD-PEEM Nano-XAFS 10m α γ α 10μm Anisotropic shape Stripe // interface(-110) bcc Related with interface? γ α 5m Why? 5μm Non-expectable magnetic domain structure in common interface Huge loss of static magnetic energy over the interface Appl. Phys. Express 3 (2010) 013001
Micromagnetics simulation fcc-ni [111] fcc Magnetic property of FeNi Coercivity(Oe ) Fe L1 0 -FeNi Ni 005 0.05 4900 MAE K 1 (erg/cc) 3.810 5 3.210 6-610 4 [110] bcc [100] bcc Easy-axis <001> <001> <111> [010] bcc Periodicity disorder order order Lattice bcc fct fcc Neel et al. J. Appl. Phys. 35 (1964) 873 Handbook of magnetic materials by Chikazumi Fe fcc-ni bcc-fe Head-on domain Stripe domain L1 0 -FeNi Tetrataenitet t it Large coercivity Large magnetic anisotropy Hard mag. Ni Tetrataenite (L1 0 -Fe 50 Ni 50 ) Affect the magnetization to surrounding Fe and Ni Appl. Phys. Express 3 (2010) 013001 bcc-fe y x z Head-on domain Stripe domain It is also correlated with whole magnetic anisotropy of iron meteorite.
Magnetic domain structure for various thickness of tetrataenite lamella Ni Tetrataenite 0nm(Ni/Fe) 400nm 600nm Fe Domain wall Head-on configuration 800nm 1000nm 1200nm * Grid size is 100nm
Summary Magnetic property of iron meteorite FeNi Widmanstatten tt apply A sort of magnetic multilayer PEEM, Magnetic domain structure @ interface Head-on Stripe Large loss in static ti magnetic energy Un-expectable Reasonable explanation Micromagnetics simulation L1 0 -FeNi
PEEM is spreading now NHK news H21.12.16 2009 12/17, (2010 1/1), (12/17 20103 20108 International Metallographic Society Dubose-Crouse Award
Current research L1 0 -FeNi Widmanstatten structure L1 0 0 L1 0 -CoPt Comparable 5mm L1 0 -FeNi Tetrataenite L1 0 -FeNi FeNi Ni Quenstion Out-of-plane Fe L1 0 -FeNi 5μm How? In-plane
Experimental Synthesis of L1 0 -FeNi (MBE) (Fe(001)/Ni(001)) 50 /Cu(001)/Au/Fe/MgO JMMM 310 (2007) 2213 J. Appl. Phys. 107 (2010) 09A716 J. Phys.: Conf. Ser. 266 (2011) 012095 SPELEEM@BL17SU SPring-8 ISS K >4810 u 4.810 6 erg/cm 3 (4.810 5 J/m 3 ) a 3.65 c 3.59 c/a 0.984 22nm(PEEM) 7.8nm(LEEM) MCDFe-L3 30um 20um vs. φ M order disorder M z 1.1T 16 M xy [010] φ [100]
Magnetic domain of L1 0 -FeNi and FeNi Disorder FeNi Order L1 0 -FeNi [100] [100] m m
Magnetic domain of L1 0 -FeNi vs. incident [010] 0 30 60 80 [100] 5m 5m 5m 5m [010] In-plane 0 30 60 80 [100] 5m 5m 5m 5m 1.1T In-plane Out-of-plane? J. Phys.: Conf. Ser. 266 (2011) 012095
In-plane and out-of-plane component Pixel-by-pixel analysis In-plane Out-of-plane y=a 0 + A 1 cos(φ+δ) 5m 5m MCD // = A 1 /cos16 MCD =A 0 /sin16 δ
Summary PEEM L1 0 -FeNi L1 0 -FeNiFeNi MBEL1 0 -FeNi L1 0 -FeNi