Colossal piezoresistance in phase separated manganites

Area of Science:

• Condensed Matter Physics
• Materials Science
• Thin Film Science

Background:

• Manganite thin films exhibit complex phase-separated states.
• Understanding strain effects on transport properties is crucial for device applications.

Purpose of the Study:

• To investigate the strain-dependent transport properties of phase-separated manganite thin films.
• To determine the conditions necessary for colossal piezoresistance (CPR).

Main Methods:

• Fabrication of (La(1-y)Pr(y))(1-x)Ca(x)MnO(3) thin films on NdGaO(3)(110) substrates.
• Application of external mechanical stress using a three-point beam bending technique.
• Measurement of resistance changes under applied strain.

Main Results:

• Colossal piezoresistance (CPR) was observed in the manganite thin films.
• Phase separation is a necessary but not sufficient condition for CPR.
• Maximum CPR is achieved when phase boundaries are mobile within a fluid-like phase-separated state.

Conclusions:

• The study elucidates the critical role of mobile phase boundaries in achieving CPR.
• Both long-range strain interactions and quenched disorder influence micrometer-scale phase separation.
• These findings provide insights into the mechanisms governing strain-induced electronic phase transitions in manganites.