Restructuring of emergent grain boundaries at free surfaces – an interplay between core stabilization and elastic stress generation

Abstract Scanning tunneling microscopy and numerical calculations are used to study the structure and relaxation of grain boundaries at the surface of planar nanocrystalline copper (111) films and bicrystals. We show that the strong energetic preference for boundary cores to lie along close-packed planes introduces a restructuring that rotates adjoining grains and generates elastic stresses in the triple junction region. The interplay of this stress field and the core stabilization determines the length scale of the restructuring and controls the shape and magnitude of the displacement field around the triple junction. Depending on the in-plane angle, restructured boundaries can extend to depths of ~ 15 nm with the associated elastic stress fields extending to even greater depths. These results point to a new mechanism of boundary relaxation at surfaces that is expected to play an important role in grain coalescence and stress evolution in growing films.

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Multilayer graphene, Moiré patterns, grain boundaries and defects identified by scanning tunneling microscopy on the m-plane, non-polar surface of SiC

Carbon ◽

10.1016/j.carbon.2014.08.028 ◽

2014 ◽

Vol 80 ◽

pp. 75-81 ◽

Cited By ~ 15

Author(s):

P. Xu ◽

D. Qi ◽

J.K. Schoelz ◽

J. Thompson ◽

P.M. Thibado ◽

...

Keyword(s):

Scanning Tunneling Microscopy ◽

Grain Boundaries ◽

Scanning Tunneling ◽

Multilayer Graphene ◽

Tunneling Microscopy ◽

Polar Surface ◽

Moire Patterns ◽

Moiré Patterns

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Mapping of local electronic properties in nanostructured CMR thin films by Scanning Tunneling Microscopy (STM) and Local Conductance Map (LCMAP)

MRS Proceedings ◽

10.1557/proc-838-o10.13 ◽

2004 ◽

Vol 838 ◽

Cited By ~ 1

Author(s):

Sohini Kar ◽

Barnali Ghosh ◽

L. K. Brar ◽

M A. Paranjape ◽

A. K. Raychaudhuri

Keyword(s):

Magnetic Field ◽

Thin Films ◽

Grain Boundaries ◽

Electronic Properties ◽

Variable Temperature ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Colossal Magnetoresistive ◽

Spatially Resolved ◽

Temperature Scanning

ABSTRACTWe have investigated the local electronic properties and the spatially resolved magnetoresistance of a nanostructured film of a colossal magnetoresistive (CMR) material by local conductance mapping (LCMAP) using a variable temperature Scanning Tunneling Microscope (STM) operating in a magnetic field. The nanostructured thin films (thickness ≈500nm) of the CMR material La0.67Sr0.33MnO3(LSMO) on quartz substrates were prepared using chemical solution deposition (CSD) process. The CSD grown films were imaged by both STM and atomic force microscopy (AFM). Due to the presence of a large number of grain boundaries (GB's), these films show low field magnetoresistance (LFMR) which increases at lower temperatures.The measurement of spatially resolved electronic properties reveal the extent of variation of the density of states (DOS) at and close to the Fermi level (EF) across the grain boundaries and its role in the electrical resistance of the GB. Measurement of the local conductance maps (LCMAP) as a function of magnetic field as well as temperature reveals that the LFMR occurs at the GB. While it was known that LFMR in CMR films originates from the GB, this is the first investigation that maps the local electronic properties at a GB in a magnetic field and traces the origin of LFMR at the GB.

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Investigation of the Effect of Microstructure and Grain Boundaries in Nanostructured CMR Thin Films Using Scanning Tunneling Microscopy (STM) and Local Conductance Map (LCMAP)

IEEE Transactions on Nanotechnology ◽

10.1109/tnano.2006.883483 ◽

2006 ◽

Vol 5 (6) ◽

pp. 707-711 ◽

Cited By ~ 4

Author(s):

Sohini Kar ◽

Jayanta Sarkar ◽

A. K. Raychaudhuri

Keyword(s):

Thin Films ◽

Scanning Tunneling Microscopy ◽

Grain Boundaries ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Effect Of Microstructure

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Scanning tunneling microscopy imaging of grain boundaries and triple junctions in copper

Materials Characterization ◽

10.1016/1044-5803(92)90036-h ◽

1992 ◽

Vol 28 (2) ◽

pp. 133-137 ◽

Cited By ~ 1

Author(s):

G.D. Bruce ◽

P. Fortier ◽

G. Palumbo ◽

J.E. Guillet ◽

G.J. Vancso

Keyword(s):

Scanning Tunneling Microscopy ◽

Grain Boundaries ◽

Scanning Tunneling ◽

Triple Junctions ◽

Tunneling Microscopy ◽

Microscopy Imaging

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Study on the Microstructure and Electrical Properties of Boron and Sulfur Codoped Diamond Films Deposited Using Chemical Vapor Deposition

Journal of Nanomaterials ◽

10.1155/2014/109869 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7

Author(s):

Zhang Jing ◽

Li Rongbin ◽

Wang Xianghu ◽

Wei Xicheng

Keyword(s):

Grain Boundaries ◽

Measurement Techniques ◽

Diamond Films ◽

Chemical Vapor ◽

Atomic Scale ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Force Microscopy ◽

Si Substrates ◽

Average Size

The atomic-scale microstructure and electron emission properties of boron and sulfur (denoted as B-S) codoped diamond films grown on high-temperature and high-pressure (HTHP) diamond and Si substrates were investigated using atom force microscopy (AFM), scanning tunneling microscopy (STM), secondary ion mass spectroscopy (SIMS), and current imaging tunneling spectroscopy (CITS) measurement techniques. The films grown on Si consisted of large grains with secondary nucleation, whereas those on HTHP diamond are composed of well-developed polycrystalline facets with an average size of 10–50 nm. SIMS analyses confirmed that sulfur was successfully introduced into diamond films, and a small amount of boron facilitated sulfur incorporation into diamond. Large tunneling currents were observed at some grain boundaries, and the emission character was better at the grain boundaries than that at the center of the crystal. The films grown on HTHP diamond substrates were much more perfect with higher quality than the films deposited on Si substrates. The localI-Vcharacteristics for films deposited on Si or HTHP diamond substrates indicate n-type conduction.

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