Enhancement of the Curie temperature in NdBaCo2O5.5 by A-site Ca substitution
- ORNL
- Argonne National Laboratory (ANL)
- Bragg Institute, ANSTO
- Northern Illinois University
Layered cobaltites RBaCo2O5.5 (R = rare earth and Y) undergo a sequence of magnetic and electronic transitions between antiferromagnetic/ferrimagnetic/paramagnetic and insulating/paramagnetic metallic states with respective transition temperatures TN ( 230 260 K) < TC ( 250 290 K) < TMI ( 360 K). We have synthesized a Nd1 xCaxBaCo2O5.5 series (0 x 0.2) of cation-[(Nd,Ca)/Ba]-ordered and oxygen vacancy-ordered materials and investigated them by neutron diffraction, magnetization, and electronic and thermal transport. We observe that upon Ca doping, TN is decreasing to 0 for x = 0.1 and TC is increasing and coincides with TMI for x > 0.12, which weakly changes with Ca substitution from 360 to 340 K. This is the largest enhancement of TC observed for these cobaltites. Unlike hole doping by adding oxygen, Ca doping does not disrupt the cation and oxygen vacancy orderings up to x = 0.20
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1052272
- Journal Information:
- Physical Review B, Vol. 86, Issue 6; ISSN 1098--0121
- Country of Publication:
- United States
- Language:
- English
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