Abstract
We demonstrate how chemical pressure affects the structural and electronic phase transitions of the quadruple perovskite CaMn7O12 by Sr doping, a compound that exhibits a charge-ordering transition above room temperature making it a candidate for oxide electronics. We have synthesized Ca1-xSrxMn7O12 (0 ≤ x ≤ 0.6) thin films by oxide molecular beam epitaxy on (LaAlO3)0.3(SrAl0.5Ta0.5O3)0.7 (LSAT) substrates. The substitution of Sr for Ca results in a linear expansion of the lattice, as revealed by X-ray diffraction. Temperature-dependent resistivity and X-ray diffraction measurements are used to demonstrate that the coupled charge-ordering and structural phase transitions can be tuned with Sr doping. An increase in Sr concentration acts to decrease the phase transition temperature (T∗) from 426 K at x = 0 to 385 K at x = 0.6. The presence of a tunable electronic phase transition, above room temperature, points to the potential applicability of Ca1-xSrxMn7O12 in sensors or oxide electronics, for example, via charge doping.
| Original language | English |
|---|---|
| Article number | 096105 |
| Journal | APL Materials |
| Volume | 5 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 1 2017 |
Funding
We thank Boris Yakshinkiy for RBS measurements at the Rutgers University Laboratory for Surface Modification. A.H. was supported by the U.S. Department of Energy (DOE), Office of Science (OS), Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education for the DOE under Contract No. DE-SC0014664. S.J.M. was supported by the Army Research Office (No. W911NF-15-1-0133). The work at ORNL was supported by U.S. DOE, OS, Basic Energy Sciences, Materials Sciences and Engineering Division (high temperature XRD characterization) and the Scientific User Facilities Division.
