Doubling the critical temperature of La_1.9Sr_0.1CuO4 thin films using epitaxial strain.
Abstract
There has been no increase in the critical temperature Tc of bulk cuprates since the discovery that the HgBa_2Ca_2Cu_3O8 + δ compound has a Tc of 133 K. However, under hydrostatic pressure (15 GPa), Tc rises to about 164 K. One way to stabilize such an increase permanently is to use the epitaxial strain in thin films. To achieve a substantial Tc increase requires (i) knowledge of the pressure, P, or strain, ɛ, derivatives of T_c; (ii) a substrate with the appropriate lattice mismatch; (iii) an optimal thickness, and (iv) a relatively defect-free growth process. We demonstrate the feasibility of this approach for thin films of the the La_1.9Sr_0.1CuO4 compound --- whose bulk critical temperature is 25 K --- tuning its critical temperature up to 49 K under compressive strain. Under tensile strain the opposite behavior is observed and the critical temperature is reduced down to 10 K.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 1998
- Bibcode:
- 1998APS..MAR.M3506L