September 2012

Journal

Enhancement of the Curie temperature in NdBaCo2O5.5 by A-site Ca substitution

By:
Kolesnik, Stanislaw K; Dabrowski, B.; Chmaissem, Omar H; Avci, Sevda ; Hodges, Jason P; Avdeev, Maxim; Swierczek, Konrad
Journal Name:
Physical Review B
Page Number:
64434-64445
Volume:
86
Issue Number:
6
Publication Date:
September 26, 2012
View DOI Listing:
https://doi.org/10.1103/PhysRevB.86.064434

Abstract

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) 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