Magnetic-field-induced spin crossover of Y-doped Pr${}_{0.7}$Ca${}_{0.3}$CoO${}_3$

Abstract

The family of hole-doped Pr-based perovskite cobaltites, Pr${}_{0.5}$Ca${}_{0.5}$CoO${}_3$ and (Pr${}_{1-y}$RE${}_y$)${}_{0.3}$Ca${}_{0.7}$CoO${}_3$ (where RE is rare earth) has recently been found to exhibit simultaneous metal-insulator, spin-state, and valence transitions. We have investigated magnetic-field-induced phase transitions of (Pr${}_{1-y}$Y${}_y$)${}_{0.7}$Ca${}_{0.3}$CoO${}_3$ by means of magnetization measurements at 4.2$-$100 K up to an ultrahigh magnetic field of 140 T with the chemical pressure varied by $y$ = 0.0625, 0.075, 0.1. The observed magnetic-field-induced transitions were found to occur simultaneously with the metal-insulator transitions up to 100 T. The obtained magnetic field-temperature ($B$-$T$) phase diagram and magnetization curves are well analyzed by a spin-crossover model of a single ion with interion interactions. On the other hand, the chemical pressure dependence of the experimentally obtained magnetization change during the phase transition disagrees with the single ion model when approaching low temperatures. The significant $y$ dependence of the magnetization change at low temperatures may arise from the itinerant magnetism of Co${}^{3+}$ in the paramagnetic metallic phase, where the chemical pressure enhances the exchange splitting by promoting the double-exchange interaction. The observed $B$-$T$ phase diagrams of (Pr${}_{1-y}$Y${}_y$)${}_{0.7}$Ca${}_{0.3}$CoO${}_3$ are quite contrary to that of LaCoO${}_3$, indicating that in (Pr${}_{1-y}$Y${}_y$)${}_{0.7}$Ca${}_{0.3}$CoO${}_3$ the high-field phase possesses higher entropy than the low-field phase, whereas it is the other way around in LaCoO${}_3$.

arXiv comment8 pages, 6 figures

References in corpus (14)

• Pressure-induced insulating state in (La,Sr)CoO${}_3$
• Transport and Magnetic Studies on the Spin State Transition of Pr1-xCaxCoO3 up to High Pressure
• Spin state ordering of strongly correlating LaCoO${}_3$ induced at ultrahigh magnetic fields
• Phase diagram and collective excitation in excitonic insulator: from the orbital physics viewpoint
• Metal-insulator transition and the Pr${}^{3+}$/Pr${}^{4+}$ valence shift in (Pr${}_{1-y}$Y${}_y$)${}_{0.7}$Ca${}_{0.3}$CoO${}_3$
• A cascade of magnetic field induced spin transitions in LaCoO3
• Excitonic condensation of strongly correlated electrons: the case of Pr${}_{0.5}$Ca${}_{0.5}$CoO${}_3$
• Crystal field and magnetism of Pr${}^{3+}$ and Nd${}^{3+}$ ions in orthorhombic perovskites
• Field-induced exciton condensation in LaCoO3
• Magnetic field effects in a correlated electron system with spin-state degree of freedom - Implication of an excitonic insulator -
• Phase transition in Pr0.5Ca0.5CoO3 and related cobaltites
• Mechanism of spin crossover in LaCoO3 resolved by shape magnetostriction in pulsed magnetic fields
• The ground state properties of the mixed-valence cobaltites Nd${}_{0.7}$Sr${}_{0.3}$CoO${}_3$, Nd${}_{0.7}$Ca${}_{0.3}$CoO${}_3$ and Pr${}_{0.7}$Ca${}_{0.3}$CoO${}_3$
• Irreversible Heating Measurement with Microsecond Pulse Magnet: Example of the alpha-theta Phase Transition of Solid Oxygen

Cited by in corpus (7)

• High-speed 100 MHz strain monitor using fiber Bragg grating and optical filter for magnetostriction measurements under ultrahigh magnetic fields
• A New Era of Excitonic Insulators
• Excitonic magnetism in $d^6$ perovskites
• Competing phases in a model of Pr-based cobaltites
• 100 MHz high-speed strain monitor using fiber Bragg grating and optical filter applied for magnetostriction measurements of cobaltite at magnetic fields beyond 100 T
• Excitonic ordering in strongly correlated spin crossover systems: induced magnetism and excitonic excitation spectrum
• Magnetostriction studies up to megagauss fields using fiber Bragg grating technique