Controlled mechnical modification of manganite surface with nanoscale resolution.
We investigated the surfaces of magnetoresistive manganites, La(1-x)Ca(x)MnO3 and La(2-2x)Sr(1+2x)Mn2O7, using a combination of ultrahigh vacuum conductive, electrostatic and magnetic force microscopy methods. Scanning as-grown film with a metal tip, even with zero applied bias, was found to modify the surface electronic properties such that in subsequent scans, the conductivity is reduced below the noise level of conductive probe microscopy. Scanned areas also reveal a reduced contact potential difference relative to the pristine surface by ∼0.3 eV. We propose that contact-pressure of the tip modifies the electrochemical potential of oxygen vacancies via the Vegard effect, causing vacancy motion and concomitant changes of the electronic properties.
The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands.
Simon J
SJ
Kelly
Yunseok
Y
Kim
Eugene
E
Eliseev
Anna
A
Morozovska
Stephen
S
Jesse
Michael D
MD
Biegalski
J F
JF
Mitchell
H
H
Zheng
J
J
Aarts
Inrok
I
Hwang
Sungtaek
S
Oh
Jin Sik
JS
Choi
Taekjib
T
Choi
Bae Ho
BH
Park
Sergei V
SV
Kalinin
Peter
P
Maksymovych