SrTiO3 could be a new persistent photoconductor

Conundrum, Wed Nov 20 2013, 08:56AM

Hi, has anyone else heard about this?
seems that a well known dielectric material under certain conditions can become an excellent conductor when exposed to light.

It seems that the mechanism was discovered by accident as is often the case with scientific discoveries, the material exhibits "persistent photoconductivity" when exposed to light of specific wavelengths.

The RTS effect may have actually been observed way back in 2003 in a related compound, in this case the effect was seen in layers of barium strontium titanate with a silver coating.
At the time no-one realised why the effect occurred nor why it seemed to vanish upon heating and re-cooling.

Am in the process of attempting replication of the experiment, in my case using microwave synthesis.

A related experiment is to attempt to dope SrTiO3 with other elements such as gallium as this might enhance the effect.
This approach has been tried by Joe Eck with Y123 (see ) and found to enhance Tc so it could work.

EDIT: Tried microwave annealing, the problem is that the MW oven wasn't designed to operate for more than an hour at a time.
It gets very very hot and the piece of ceramic I used gets red to yellow (600+ Celsius) but not for long.

EDIT 2: Eck seems to have found a link between dielectric constant and Tc, noticing that manganese dioxide (MnO2) added to existing superconductors in the right amounts increases Tc and possibly could be used with BSCCO as well..

I had a thought about BiSbW as well, possibly might do interesting things wrt electromagnetic fields in a narrow temperature range around 297.4K, possibly in a similar fashion to Eck's claimed resonant superconductor at 109K.

-A
#include "whydidntithinkofthisfirst.h"

edit: cleaned up and added new content