MagTEM at the University of Glasgow

In 2012 the Materials and Condensed Matter Physics Group opened the MagTEM facility at the University of Glasgow. MagTEM is a JEOL ARM (Atomic Resolution Microscope) 200cF which is a scanning transmission electron microscope (STEM) with aberration correction provided by CEOS. Aberration correction allows world leading performance of this instrument, and the capability of the instrument is summarised below:

  • standard mode STEM imaging achieves atomic imaging with a spatial resolution of 0.078 nm
  • world’s first magnetic STEM imaging in Lorentz mode with sub nanometre resolution demonstrated [1]
  • spectroscopic chemical mapping (electron energy loss spectroscopy (EELS)) can be performed with a Gatan Quantum 965 GIF 
  • energy dispersive spectroscopy (EDS) with Bruker XFlash 60 X-ray detection system
  • in-situ capabilities are provided via specialised and customised sample rods allowing cooling/heating, electrical current application and tomographic reconstruction.
MagTEM has enabled the group to diversify its research base and currently provides support for research projects funded at a level of >£4M, including the recent award of a noble gas FIB (focused ion beam) instrument for improved TEM sample preparation and novel nanopatterning.
In summary MagTEM has become an essential tool across nano-materials science and has enabled collaborations including high resolution studies of a variety of magnetic systems [2,3,4], functional oxides [5], organic electronics [6], and the origins of nanoparticles implicated in the onset of Alzheimer's disease [7].
 
Further information about the activities of the MCMP group and enquiries regarding the use of the Kelvin Nanocharacterisation Facilities can be found at: http://www.gla.ac.uk/schools/physics/research/groups/mcmp/
 
High resolution magnetic structure imaging of skyrmions in FeGe. The left hand images show two components of magnetic induction (upper) together with the magnitude of the signal and a colour representation (lower). The magnetic structure of the vortex is an in-plane rotation of magnetisation about a central core that is directed out of plane. A bivariate histogram of the in-plane induction components shows a clear six-fold symmetry of the skyrmion structure.
 
Aberration correction enables individual atoms to be visualised directly, here (top) at the interface of a thin film perovskite oxide crystal system, where the heaviest atoms appear brightest and the periodic nature of the crystal structure is clear. Spectroscopic measurements are also possible on the atomic scale (bottom), allowing the identity of individual atoms to be determined and enabling studies of nanoscale chemistry.
 
[1] Ultramicroscopy 152 (2015) 57
Aberration corrected Lorentz scanning transmission electron microscopy,
S McVitie, D McGrouther, S McFadzean, DA MacLaren, KJ O’Shea and MJ Benitez 
 
[2] Nature Comm. 6 (2015), 8957 
Magnetic microscopy and topological stability of homochiral Néel domain walls in a Pt/Co/AlOx trilayer,
MJ Benitez, A Hrabec, AP Mihai, TA Moore, G Burnell, D McGrouther, CH Marrows & S McVitie 
 
[3] New J. Phys. 18 (2016), 095004
Internal structure of hexagonal skyrmion lattices in cubic helimagnets
D McGrouther, R J Lamb, M Krajnak, S McFadzean, S McVitie, R L Stamps, A O Leonov, A N Bogdanov and Y Togawa 
 
[4] Nature 524 (2015) 69
Beating the Stoner criterion using molecular interfaces,
F Al Ma’Mari, T Moorsom, G Teobaldi, W Deacon, T Prokscha, H Luetkens, S Lee, GE Sterbinsky, DA Arena, DA MacLaren, M Flokstra, M Ali, MC Wheeler, G Burnell, BJ Hickey and O Cespedes.
 
[5] NanoLetters 16 (2016) 5291
Dynamical torque in CoxFe3-xO4 nano-cube thin films characterized by femtosecond magneto-optics: a π-shift control of the magnetization precession, 
M Vomir, R Turnbull, I Birced, P Parreira, DA MacLaren, SL Lee, P André and J-Y Bigot.
 
[6] J. Mater. Chem. C 2 (2014) 245
Structure–function relations in diF-TES-ADT blend organic field effect transistors studied by scanning probe microscopy,
AB Naden, J Loos and DA MacLaren.
 
[7] PNAS 113 (2016) 10797
Magnetite pollution nanoparticles in the human brain,
BA Maher, IAM Ahmed, V Karloukovski, DA MacLaren, PG Foulds, D Allsop, DMA Mann, R Torres-Jardón and L Calderon-Garciduenas