JEOL news Latest number Abstract

Vol.50, 2015

Lorentz TEM Study on Magnetic Skyrmions and Their Dynamics

Xiuzhen Yu1 and Yoshinori Tokura1,2
1 RIKEN Center of Emergent Matter Science (CEMS)
2 Department of Applied Physics, The University of Tokyo
The magnetic skyrmion is a vortex-like topological particle, in which spins swirl from the north-pole in the core to the south-pole in the outermost circle of the vortex. Nanometric skyrmions realized recently in magnetic materials are promising for applications to the high-density and low-power-consumption magnetic memory. The key research issue for practical applications is to realize and manipulate such a nanoscale spin-ensemble object in a well controlled manner. We report here the Lorentz transmission electron microscopy (LTEM) studies on magnetic skyrmions and their dynamics under external magnetic fields, spin-polarized electric current and irradiated electron beam in helimagnets/uniaxial-ferromagnets with non-centrosymmetric/centrosymmetric structures. We have developed a useful technique not only to create skyrmions by a precise control of the magnetic field in a standard transmission electron microscope (TEM), but also to view the skyrmions and their dynamics in real-space in the LTEM mode.

Quantitative ADF STEM for Catalyst Nanoparticle Metrology

Peter D Nellist1, Lewys Jones1, Katherine E MacArthur1 and Dogan Ozkaya2
1 University of Oxford, Department of Materials
2 Johnson Matthey Technical Centre
A method to reconstruct the three-dimensional structure of catalyst nanoparticles from single projections is
described. The aim is to develop a method by which statistically meaningful measurements of heterogeneous
catalyst systems can be made and subsequently related to catalyst properties with goal of assisting with the rational
design of new catalysts. A method for the careful calibration of annular dark-field STEM images is described.
Use is made of scattering cross-sections to enable comparison with simulation to allow the number of atoms in
atomic columns to be determined. Finally, an energy minimization method is used to finalise the three-dimensional
structure.

Quantitative Characterization of Magnetic Materials Based on Electron Magnetic Circular Dichroism with Nanometric Resolution Using the JEM-1000K RS Ultra-High Voltage STEM

Shunsuke Muto1, Jan Rusz2, Kazuyoshi Tatsumi1, Roman Adam3, Shigeo Arai1,
Vancho Kocevski2, Peter M. Oppeneer2, Daniel E. Bürgler3 & Claus M. Schneider3
1Division of Green Materials, EcoTopia Science Institute, Nagoya University, Japan
2Department of Physics and Astronomy, Uppsala University, Sweden
3Peter Grünberg Institut, Forschungszentrum Jülich GmbH, Germany
Electron magnetic circular dichroism (EMCD) allows the quantitative, element-selective determination of spin and orbital magnetic moments in a manner similar to its better-established X-ray counterpart, X-ray magnetic circular dichroism (XMCD). As an advantage over XMCD, EMCD measurements are performed using transmission electron microscopes, which are routinely operated at sub-nanometer resolution. However, because of the low signal-to-noise ratio of the EMCD signal, it has not yet been successful to obtain quantitative information from EMCD signals at the nanometer scale. In the present article, we demonstrate a new approach to EMCD measurements that takes most of the higher accelerating voltage of the incident electrons, which considerably enhances the applicability of the technique. The statistical analysis introduced here yields robust quantitative EMCD signals. In the present scheme, quantitative magnetic information can be routinely obtained using electron beams of only a few nanometers in diameter, without imposing any restrictions on the crystalline order of the specimen.

Application of Atomic-Resolution Energy-Dispersive X-ray Spectroscopy to the Study of Structures of Decagonal Quasicrystals

Kenji Hiraga1 and Akira Yasuhara2
1 Institute for Materials Research, Tohoku University
2 EM Business Unit, JEOL Ltd.
We give an overview of recent studies for chemical ordering in Al-Co-Ni crystalline phases related to Al-Co-Ni decagonal quasicrystals (DQCs), and Al-Mn-Pd DQC, by atomic-resolution energy-dispersive X-ray spectroscopy (EDS) combined with Cs-corrected scanning transmission electron microscopy (STEM). In order to avoid the electron damage by the strong electron beam in a field-emission gun installed to a Cs-corrected STEM and long exposure times required to obtain high-resolution EDS maps, atomic-resolution EDS maps were obtained by integrating many sets of EDS data taken from fresh areas at each time by shifting the sample so that the same structure unit is always placed at the definite position on the STEM monitor. On the observed EDS maps, Co and Ni atomic positions
in the Al-Co-Ni phases, and Mn- and Pd-enriched positions in the Al-Mn-Pd DQC can be clearly detected.

Dressing Living Organisms in the NanoSuit® for FE-SEM Observation

Takahiko Hariyama and Yasuharu Takaku
Departments of Biology, Hamamatsu University School of Medicine
Scanning electron microscopy (SEM) has made remarkable progress, and has become an essential tool for observing biological materials. However, they are required to be completely dry, since the specimen chamber is at high vacuum. The living soft-bodied organisms require chemical fixation and following various complex procedures to preserve and stabilize their structure. In this article, we demonstrate a new method with which living organisms can be observed by a field emission (FE) SEM. Using this method, active movements of living animals were observed in vacuo (10-3-10-5 Pa) by protecting them with a coating of thin polymer membrane, the NanoSuit®, and it was found that the surface fine structure of living organisms is very different from that of traditionally treated amples. After observation of living organisms, despite the high vacuum it was possible to rear many of them subsequently in normal culture conditions. This method will be useful for numerous applications, particularly for electron microscopic observations in the life sciences.

Serial Block Face Scanning Electron Microscopy Using the JEOL JSM-7100F with Gatan 3View 2XP at King’s College London –UK

R. A. Fleck1, G. Vizcay1, G. Neves3, F. W. Grillo3, J. Burrone3, M. Green4, A. Bullen2
1 Centre for Ultrastructural Imaging, King’s College London
2 Centre for Auditory Research, UCL Ear Institute
3 MRC Centre for Developmental Neurobiology, King’s College London
4 Department of Physics, King’s College London
In this article, we describe recent progress implementing serial block face scanning electron microscopy (SBF-SEM) using a Gatan 3View system on a JEOL Field Emission Scanning Electron Microscope. We show the versatility of the system and discuss best practice in preparing tissues for this technique and for post processing of data. Moreover, we describe a number of important technical improvements in the performance of the SBF-SEM, which we have implemented in partnership with JEOL and Gatan.

Detailed Structural Characterization of Polymers by MALDI-TOFMS with a Spiral Ion Trajectory

Hiroaki Sato
National Institute of Advanced Industrial Science and Technology
Detailed structural characterization of polymers is important because molecular properties of polymers strongly influence the material properties. Structural characterization of polymers have been performed by various instrumental analyses such as spectroscopic techniques (nuclear magnetic resonance spectroscopy: NMR, infrared spectroscopy: IR), chromatographic techniques ((pyrolysis-)gas chromatography: (Py-)GC , high performance liquid chromatography: HPLC, size
exclusion chromatography: SEC), as well as mass spectrometry. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) can observe molar mass of each polymer chain without fragmentation. Therefore, it exhibits its power for the determination of detailed polymer structures such as repeating units, end-groups, molecular weight distribution, and copolymer compositions. However, characterization of industrial complicated polymers such as copolymers and polymer blends are difficult by conventional MALDI-TOFMS, because a mass of polymer chains within complex polymeric materials increases the likelihood of isobaric interference, in which the peaks of different chemical compositions with the same nominal mass overlap. Peak separation of isobaric 
components requires high-resolution mass spectrometry. This report first describes brief features of high-resolution MALDITOFMS with a spiral ion trajectory, termed “MALDI spiral-TOFMS”, and then some applications of MALDI spiral-TOFMS for a detailed structural characterization of complicated polymers are presented.

13C and 1H Solid-state NMR of Proteins and Other Systems under Ultra-Fast MAS at 80-100 kHz and Beyond

Songlin Wang and Yoshitaka Ishii
Department of Chemistry, University of Illinois at Chicago
This article highlights a couple of drastic changes in the field of protein solid-state NMR (SSNMR) associated with ultra-fast magic-angle spinning (MAS) at 80 kHz or higher in a high magnetic field (1H NMR freq. 750 MHz). We discuss how a traditional cross-polarization MAS (CP-MAS) scheme has been transformed into an efficient lowpower RF scheme suited for high-field applications under ultra-fast MAS (UFMAS). We also discuss a nano-molescale SSNMR analysis of protein side chains by 1H detection. It is demonstrated that 1H-detected 2D and 3D SSNMR analyses are feasible for ~10 nmol of a stereo-selectively 2H- and 13C-labled ubiquitin within 2.5 h and 3 days at a spinning speed of 80 kHz. The data suggest that UFMAS approach is likely applicable to a variety of larger proteins.

Development of Super-High Sensitivity EDS System for GRAND ARM (JEM-ARM300F)

E. Okunishi1, T. Sasaki1, H. Sawada1, Y. Jimbo1, Y. Iwasawa2, K. Miyatake2,
S. Yuasa1, I. Onishi1, M. Mita2, T. Kaneyama1 and Y. Kondo1
1 EM Business Unit, JEOL Ltd.
2 EC Business Unit, JEOL Ltd.
We developed a 300 kV Super-high resolution electron microscope, GRAND ARM (JEM-ARM300F) [1] (Fig. 1). The GRAND ARM is equipped with a variety of innovative components. These revolutionized components include 1) a new aberration corrector (ETA Corrector developed by JEOL), 2) COSMO System to control the corrector, 3) two types of newly developed objective polepieces: FHP (full high resolution polepiece) for high resolution imaging and WGP (wide gap 
polepiece) for multi-purpose microscopy, 4) a highly-stable electric circuit, mechanical system and microscope column, and 5) STEM detectors optimized for a wide range of accelerating voltages. In the GRAND ARM, STEM image resolution of 63 pm is guaranteed, Furthermore, recently, an unprecedented STEM
resolution better than 50 pm has been achieved as its best performance (Fig. 2).

Newly Developed Soft X-ray Emission Spectrometer, SS-94000SXES

Masaru Takakura1, Takanori Murano1, and Hideyuki Takahashi2
1 SA Business Unit, JEOL Ltd.
2 Global Business Promotion Division, JEOL Ltd.
JEOL’s SS-94000SXES is a brand-new spectrometer which can detect ultra-soft X-ray in an energy range from 50 to 210 eV. The characteristic X-ray in the energy range includes the emission spectra based on the valance band transitions of many elements. Soft X-ray Emission Spectrometer (SXES) enables higher energy resolution than that of the conventional EPMA. Thus, this spectrometer is an instrument being applicable to chemical bonding state analysis. On the other hand, whole elemental analysis needs to measure the characteristic X-rays at least up to 10 kV which are generated by deeper core level transitions than those of soft X-rays. Accordingly, SXES is used in conjunction with the wavelength dispersive X-ray spectrometers (WDSs) including some of analyzing crystals and
the energy dispersive X-ray spectrometer (EDS). In this paper, our new soft X-ray emission spectrometer, SS-94000SXES will be introduced, and its specification and application to some materials will be shown.

Additional Ar-Ion Etching of FIB-Prepared TEM Samples using Ion Slicer

T. Mihira1, N. Endo2, H. Hashiguchi2 and T. Suzuki1
1 IB Business Unit, JEOL Ltd.
2 EM Business Unit, JEOL Ltd.
Additional Ar-Ion Etching method using the Ion Slicer (Ion Slicer Finishing Method) was developed. This new method is intended to improve the quality of a thin-film sample prepared by FIB while maintaining advantages of FIB thinning. Improvement in the quality of the thinned sample is achieved by irradiating the sample with a lowaccelerating voltage Ar-ion beam after FIB processing using the Ion Slicer, an ion-milling thin-film sample preparation tool. Furthermore, the development of the special-shape FIB grid and the FIB-Ion Slicer common holder facilitated the transfer of the sample from the FIB system into the Ion Slicer, and improved the efficiency of the samplepreparation procedures.

New Gas Chromatography/High Resolution Time-of-Flight Mass Spectrometer JMS-T200GC “AccuTOF GCx”

Masaaki Ubukata
JEOL USA, Inc.
As mass spectrometry (MS) is used in a wide range of scientific fields today, different types of MS systems are available to meet different research objectives and applications. Compared to other scientific instruments, the most powerful feature of MS is its high sensitivity. Some of the commercial MS systems can easily detect and analyze ultra trace components in the fg (10-15 g) order. Time-of-flight MS (TOFMS) and magnetic sector MS systems, capable of acquiring high resolution (HR) and high mass accuracy data, make it possible to determine elemental compositions from the exact mass data of the detected ions. Thus, MS is being used in a variety of fields as a powerful analytical instrument for qualitative and quantitative examination of ultra trace components. In the fall of 2004, JEOL announced the JMS-T100GC AccuTOF GC, the first gas chromatography/high resolution time-of-flight mass spectrometer (GC/HR-TOFMS) developed in
Japan. The system has been received well by many users. JEOL has recently completed the 4th generation GC/HR-TOFMS, JMS-T200GC AccuTOF GCx, featuring higher sensitivity and higher mass resolution. In this article, we will provide an overview of the AccuTOF GCx, and describe its advantages in comparison to the original system.