Facilities and Instrumentation
There
are three unique SPMs in my lab: a homemade Helium3-magnetic
force microscope (He3-MFM), a variable temperature-MFM (VT-MFM), an ultrahigh vacuum-low
temperature-scanning tunnel microscope (UHV-LT-STM).
Homemade He3-MFM with 14 T magnet
Our homemade He3-MFM is capable of high spatial resolution magnetic imaging with high
sensitivity at ulra-low temperature (300 mK) with in situ high magnetic field (14 T), high voltage (1 kV), and transport measurements. The
unique combination of in situ
capabilities of our MFM allows us to explore novel magnetic and electric
properties of almost any new materials at quantum limit.
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Base T: ~253 mK
Sample T: 350 mK-RT
He-3 Holding Time
4K mode: ~88 h
1K mode: >150 h
14 T (Out-of-plane)
High sensitivity
in-situ transport
in-situ high voltage
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Homemade VT-MFM with in situ high magnetic/electric
fields
Our homemade VT-MFM is the only machine in
the world that is capable of high spatial resolution magnetic imaging with high
sensitivity in a wide temperature range (2-300 K) with in situ high magnetic field (8 T) and high voltage (1 kV). The
unique combination of in situ
capabilities of our MFM allows us to explore novel magnetic and electric
properties of almost any new materials at extreme conditions. Examples include
correlated net moments at multiferroic domain walls,
magnetic inhomogeneity in ultra-thin magnetic films and unconventional
pancake-like domains in multiferroics. In addition,
we have developed unprecedented Magnetoelectric Force
Microscopy (MeFM) for visualizing magnetoelectric
domains with submicron resolution.
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Key features
Variable T
(2 - 300 K) & high H (8 T)
High vacuum
(<10-6 mbar)
High
resolution (50 - 100 nm)
High
sensitivity (~ )
Mmin ~
Antiferromagnetic domain walls
in-situ high voltage (1 kV)
10 MV/m
for thickness ~ 0.1 mm
MeFM
in-situ transport
AHE, THE, etc.
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MFM inside
8 T magnet
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MFM head
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An ultra-high-vacuum low
temperature scanning tunnerling microscope
(UHV-LT-STM) from Omicron Nanotechnology
has been installed in our SPM lab. The system consists of a LT-STM
analysis chamber, and dedicate preparation chamber and a load-lock (FEL). The base pressure of the STM chamber is
below 1e-11 mbar. The base temperature is 4.5 K. The
dedicate preparation chamber for in situ tip and surface preparation is
installed. In collaboration with Prof. M.
Bode at the Universitate Wuerzburg,
we are developing a novel spin polarized-STM (SP-STM) technique to visualize
atomic scale magnetic structure in novel magnetic materials.
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Key features
- Ultra High Vacuum (UHV)
- Pbase < 10-11 mbar
- Low temperature
- Tbase ~ 4.5 K
- Low vibration
- z noise ~ 1-2 pm
- Tip/sample preparation
- Tip prep tool
- Button heater (1000 oC)
- Sputter gun
- RGA
- Evaporators
- ...
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UHV-LT-STM
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Room temperature AFM
A multi-mode atomic force microscope (MM-AFM,
Bruker) with an extender that is capable of all AFM modes (contact, tapping,
PFM, MFM/EFM, SSPM, cAFM, etc.) at ambient condition. The commercial unit is
connected with dedicate electric cables for high sensitivity background-free piezoresponse force microscopy (PFM) measurements
(~0.1 pm/V with 5 V modulation) using a dedicate lock-in amplifier (SR 830).
Other SPM facilities
Besides developing
experimental tools and techniques in-house, we are also collaborating with
facility scientists in the Center for Nanoscale
Materials (CNM) at Argonne National Laboratory (ANL) to expand our SPM
capabilities by utilizing their advanced SPM instruments. At the same time, we are implementing various
advanced SPM techniques at CNM so that other facility users from the research
community can benefit from our SPM expertise.