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This evaluation report discusses the use of Scanning Probe Microscopy (SPM) techniques to study the domain structures and temperature dependence of Barium Titanate and Bismuth Ferrite-Barium Titanate samples. The report includes topography images and domain distribution analysis obtained using various measuring modes.
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Sample evaluation for Dr. Sithipong W.July 2011 By Mitko Sergey NT- MDT Russia 124482, Moscow. K.100 Office : (+7 499) 735-1598 Cell: (+7 916) 221-02-05 Fax: (+7 499) 735-64-10 http:\\www.ntmdt.com
SPM configuration and scanning mode • SPM device: Ntegra Prima, NT MDT. • Measuring modes: PFM,MFM,scanning-by-tip mode (capacitance sensors). • Cantilevers:DCP20 (nominal tip radius ~20 nm), NSG01/Co (nominal tip radius ~10 nm) • Heating stage: SU 045 NTF • Anti-vibration table: Active isolation tableHalcyonics Mode 1+ • Acoustic enclosure: Hood
Two samples were evaluated: Sample 1: BariumTitanate ( Single crystal) Sample 2: Bismuth Ferrite – Barium Titanate (BF-BT) Sample 1 was glued to conductive scotch (Carbon) and grounded. AC voltage was applied to sample through the conductive tip. Sample 2 was just glued to sample holder.
Sample 1 : Barium Titanate (T = 24 C ) On the upper picture you can see the topography picture, on the right the image of the vertical domains: MAG (upper), Phase (bottom). During the experiment AC voltage was applied to the sample on the frequency of 700kHz with amplitude of 10V.No horizontal domains were found. Room temperature.
Sample 1 : Barium Titanate (T = 50 C) On the upper picture you can see the topography picture, on the right the image of the vertical domains: MAG (upper), Phase (bottom). During the experiment AC voltage was applied to the sample on the frequency of 1523kHz with amplitude of 10V. T = 50 C.
Sample 1 : Barium Titanate (T = 100 C) On the upper picture you can see the topography picture, on the right the image of the vertical domains: MAG (upper), Phase (bottom). During the experiment AC voltage was applied to the sample on the frequency of 1523kHz with amplitude of 10V. T = 100 C. Reverce direction.
Sample 1 : Barium Titanate (Temperature dependence) This sequence shows the changing in domain structure due to temperature increasing. We can clearly see that after Curie point domains disappear.
Sample 1 : Barium Titanate (Temperature dependence) This sequence shows the changing in domain structure due to temperature decreasing. We can clearly see that after Curie point domains appear.
Domain reverse test (BaTi) Domain reversing test was performed on Barium Titanate sample, where a small square area (7x7um) was scanned with positive voltage (10V) applied to the tip. Then smaller area (5x5um) was scanned with negative voltage (-10V) applied to the tip.Then the bigger area (10x10um) was scanned in PFM mode and it is clear that small area has domains oriented in one direction, bigger in opposite, whereas all rest areas have no changes.
Sample 2 : BF –BT (Room temperature) This picture was obtained by using standard ac-MFM mode. Left one shows Topography. Right one magnetic domain distribution.
Sample 2 : BF –BT (T=75C) This picture was obtained by using standard ac-MFM mode (same place). Left one shows Topography. Right one magnetic domain distribution.
Sample 2 : BF –BT (T=100C) This picture was obtained by using standard ac-MFM mode (same place). Left one shows Topography. Right one magnetic domain distribution.
Sample 2 : Bismuth Ferrite -Barium Titanate (BF-BT ) Temperature dependans. This sequence shows the changing in magnetic domain structure due to temperature increasing from room temperature to 140C.
Summary. • With using PFM mode we can clearly see the change in the piezo domains due to temperature changing. • With using MFM mode we can clearly see the change in the magnetic domains due to temperature changing.
