TY - JOUR
T1 - First-order phase transition versus spin-state quantum-critical scenarios in strain-tuned epitaxial cobaltite thin films
AU - Dewey, John E.
AU - Chaturvedi, Vipul
AU - Webb, Tatiana A.
AU - Sharma, Prachi
AU - Postiglione, William M.
AU - Quarterman, Patrick
AU - Balakrishnan, Purnima P.
AU - Kirby, Brian J.
AU - Figari, Lucca
AU - Korostynski, Caroline
AU - Jacobson, Andrew
AU - Birol, Turan
AU - Fernandes, Rafael M.
AU - Pasupathy, Abhay N.
AU - Leighton, Chris
N1 - Publisher Copyright:
© 2024 American Physical Society.
PY - 2024/2/1
Y1 - 2024/2/1
N2 - Pr-containing perovskite cobaltites exhibit unusual valence transitions, coupled to coincident structural, spin-state, and metal-insulator transitions. Heteroepitaxial strain was recently used to control these phenomena in the model (Pr1-yYy)1-xCaxCoO3-δ system, stabilizing a nonmagnetic insulating phase under compression (with a room-temperature valence/spin-state/metal-insulator transition) and a ferromagnetic (FM) metallic phase under tension, thus exposing a potential spin-state quantum-critical point. The latter has been proposed in cobaltites and can be probed in this system as a function of a disorder-free variable (strain). We study this here via thickness-dependent strain relaxation in compressive SrLaAlO4(001)/(Pr0.85Y0.15)0.70Ca0.30CoO3-δ epitaxial thin films to quasicontinuously probe structural, electronic, and magnetic behaviors across the nonmagnetic-insulator/FM-metal boundary. High-resolution x-ray diffraction, electronic transport, magnetometry, polarized neutron reflectometry, and temperature-dependent magnetic force microscopy provide a detailed picture, including abundant evidence of temperature- and strain-dependent phase coexistence. This indicates a first-order phase transition as opposed to spin-state quantum-critical behavior, which we discuss theoretically via a phenomenological Landau model for coupled spin-state and magnetic phase transitions.
AB - Pr-containing perovskite cobaltites exhibit unusual valence transitions, coupled to coincident structural, spin-state, and metal-insulator transitions. Heteroepitaxial strain was recently used to control these phenomena in the model (Pr1-yYy)1-xCaxCoO3-δ system, stabilizing a nonmagnetic insulating phase under compression (with a room-temperature valence/spin-state/metal-insulator transition) and a ferromagnetic (FM) metallic phase under tension, thus exposing a potential spin-state quantum-critical point. The latter has been proposed in cobaltites and can be probed in this system as a function of a disorder-free variable (strain). We study this here via thickness-dependent strain relaxation in compressive SrLaAlO4(001)/(Pr0.85Y0.15)0.70Ca0.30CoO3-δ epitaxial thin films to quasicontinuously probe structural, electronic, and magnetic behaviors across the nonmagnetic-insulator/FM-metal boundary. High-resolution x-ray diffraction, electronic transport, magnetometry, polarized neutron reflectometry, and temperature-dependent magnetic force microscopy provide a detailed picture, including abundant evidence of temperature- and strain-dependent phase coexistence. This indicates a first-order phase transition as opposed to spin-state quantum-critical behavior, which we discuss theoretically via a phenomenological Landau model for coupled spin-state and magnetic phase transitions.
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U2 - 10.1103/PhysRevB.109.054419
DO - 10.1103/PhysRevB.109.054419
M3 - Article
AN - SCOPUS:85185409084
SN - 2469-9950
VL - 109
JO - Physical Review B
JF - Physical Review B
IS - 5
M1 - 054419
ER -