Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
800 nm x 800 nm<br />
Polarization Difference Maps (PDMs) --- A technique to intuitively visualize ferroelastic and ferroelectric switching<br /...
Three dimensional (3D) Piezoresponse Force Microscopy (PFM)<br />VPFM<br />LPFM 2<br />LPFM 1<br />Po<br />Single crystal ...
Obtain a PDM<br />|Pbefore-   Pafter| =  Pdifference<br />LPFM1<br />LPFM2<br />VPFM<br />Assign color<br />1 μm x 1 μm<br...
Experiments: PDM to study ferroelectric/ferroelastic switching<br />Without PDM, 6 PFM phase images are needed to identify...
all 6 switching types appeared (IIIV) <br />2<br />6<br />4<br />5<br />1<br />3<br />(PDM of IIIV)<br />1 μm x 1 μm<br ...
surprisingly large amount of 90o switching, and small amount of 180o switching (IIIV)<br />PDM of II  IV<br />Dark(0°),G...
180o switching consisting of 2 successive 90o switching!<br />PDM of II III<br />PDM of I II<br />PDM of I III<br />I<b...
Domain relaxation by lateral only 90o switching (III)<br />11, 4, 6<br />1 μm x 1 μm<br />(PDM of III)<br />Driven by n...
Vertical switching include both 180o and 90o switching (IIIV)<br />12, 3, 5<br />(PDM of IIIII)<br />1 μm x 1 μm<br />A...
Upcoming SlideShare
Loading in …5
×

3D PFM PDMs

1,036 views

Published on

A technique we developed to identify ferroelectric and ferroelastic switching, published in Journal of Applied Physics

  • Be the first to comment

  • Be the first to like this

3D PFM PDMs

  1. 1. 800 nm x 800 nm<br />
  2. 2. Polarization Difference Maps (PDMs) --- A technique to intuitively visualize ferroelastic and ferroelectric switching<br />Focus on the CHANGE of polarization during switching:<br />Decompose a polarization vector into components (Px, Py, Pz), measured by three dimensional (3D) Piezoresponse Force Microscopy (PFM)<br />Distinguish 6 types of switching by different combinations of “switched” and “un-switched” states of Px, Py, Pz (given by LPFM1, LPFM2, VPFM)<br />Each scanned pixel is assigned a color according to its switching type<br />11 (0o): None switch <br />12 (180o): All switch <br />13 (90o): Only VPFM switches <br />14 (90o): Both LPFM switches <br />15 (90o): One LPFM and VPFM switch <br />16 (90o): Only one LPFM switches <br />
  3. 3. Three dimensional (3D) Piezoresponse Force Microscopy (PFM)<br />VPFM<br />LPFM 2<br />LPFM 1<br />Po<br />Single crystal PZT film<br />Vertical bend of the cantilever<br />VPFM<br />Lateral twist of the cantilever<br />LPFM<br />
  4. 4. Obtain a PDM<br />|Pbefore- Pafter| = Pdifference<br />LPFM1<br />LPFM2<br />VPFM<br />Assign color<br />1 μm x 1 μm<br />11 (0o): None switch (All dark)<br />12 (180o): All switch <br />13 (90o): Only VPFM switches <br />14 (90o): Both LPFM switches <br />15 (90o): One LPFM and VPFM switch <br />16 (90o): Only one LPFM switches <br />
  5. 5. Experiments: PDM to study ferroelectric/ferroelastic switching<br />Without PDM, 6 PFM phase images are needed to identify the switching type for only 1 grain<br />With PDM, the switching types for all grains can be shown simultaneously in 1 PDM <br />
  6. 6. all 6 switching types appeared (IIIV) <br />2<br />6<br />4<br />5<br />1<br />3<br />(PDM of IIIV)<br />1 μm x 1 μm<br />11 (0o):(0)(0)(0)<br />12 (180o):(1)(1)(1)<br />13 (90o): (0)(0)(1)<br />14 (90o): (1)(1)(0)<br />15 (90o): (1)(0)(1) or (0)(1)(1)<br />16 (90o): (1)(0)(0) or (0)(1)(0)<br />(0) for “un-switched”, (1) for “switched”<br />1<br />6<br />4<br />3<br />5<br />2<br />
  7. 7. surprisingly large amount of 90o switching, and small amount of 180o switching (IIIV)<br />PDM of II  IV<br />Dark(0°),Green(90°), bright(180°)<br />In our polycrystalline thin film:<br />Less than 5% of grains switched 180o<br />More than 50% of grains switched 90o<br />In epitaxial thin films (of the same thickness and composition):<br />100% 180o switching<br />1 μm x 1 μm<br />In addition: 90o switched grains are connected, potentially triggered by neighboring grains<br />Nagarajan, V., et al., Dynamics of ferroelastic domains in ferroelectric thin films. Nat Mater, 2003. 2(1): p. 43-47.<br />
  8. 8. 180o switching consisting of 2 successive 90o switching!<br />PDM of II III<br />PDM of I II<br />PDM of I III<br />I<br />First direct observation<br />Previously predicted by statistical XRD <br />II<br />III<br />
  9. 9. Domain relaxation by lateral only 90o switching (III)<br />11, 4, 6<br />1 μm x 1 μm<br />(PDM of III)<br />Driven by neighboring grains, systematic study of the neighboring grain effects is ongoing <br />1<br />6<br />4<br />3<br />5<br />2<br />
  10. 10. Vertical switching include both 180o and 90o switching (IIIV)<br />12, 3, 5<br />(PDM of IIIII)<br />1 μm x 1 μm<br />A reversal of vertical applied E field leads to vertical (both 180o and 90o) switching<br />1<br />6<br />4<br />3<br />5<br />2<br />

×