Effect of strain on manganites
We have studied the effect of the application of direct
mechanical stress on thin films of the hole-doped manganese oxide (manganite)
(La1-yPry)1-xCaxMnO3 (LPCMO). The two competing phases in manganites are the pseudocubic
ferromagnetic metallic (FMM) phase and the orthorhombic charge-ordered insulating (COI) phase.
Due to the different structures of the FMM and COI phases, manganites are susceptible to
mechanical stresses. The traditional methods of applying stress on oxide thin films
result in different growth modes which makes it difficult to quantify the strain in
the thin film. Using a calibrated screw we applied direct mechanical stress on the
substrate (Fig. 1) and measured the change in the phase diagram of the manganite as a function
of strain (Fig. 2). Our results show that the effect of strain is the largest in the fluid phase
separated region of the phase diagram, where we observe a strain-induced change in
resistance of about 5 orders of magnitude.
Fig. 1. Application of stress using three point beam bending. |
Fig. 2. Change in the R vs. T curves of LPCMO under strain. |