Spin-state transition in Pr<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub></mml:math>Ca<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mrow><mml:mn>0.5</mml:mn></mml:mrow></mml:msub></mml:math>CoO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>3</mml:mn></mml:msub></mml:math>analyzed by x-ray absorpt

Herrero‐Martín, Javier; García-Muñoz, J. L.; Kvashnina, Kristina O.; Gallo, Erik; Subı́as, G.; Alonso, J. A.; Barón-González, A. J.

doi:10.1103/physrevb.86.125106

Cited by 45 publications

(57 citation statements)

References 40 publications

(58 reference statements)

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“…The theoretical hypothesis about the crucial role of variable praseodymium valence was experimentally supported by the observations of a Schottky peak in the low temperature specific heat of (Pr 1−y Y y ) 0.7 Ca 0.3 CoO 3 ( y=0.075 and 0.15), 12 and by the x-ray absorption near-edge structure (XANES) spectra at the Pr L 3 edge directly. [13][14][15][16] It is widely desirable to use a single crystal or an epitaxial film for the physical investigation. In the La 1−x Sr x CoO 3 system, single crystals and thin films have been fabricated and investigated.…”

Section: -2mentioning

confidence: 99%

Electrical resistivity anomaly in (Pr1−yMy)1−xCaxCoO3 epitaxial films (M=Y, Gd) fabricated by pulsed laser deposition

et al. 2016

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(Pr1−yMy)1−xCaxCoO3 epitaxial films (M=Y, Gd) have been successfully fabricated by pulsed laser deposition on the single crystal substrates with different lattice constant. The polycrystalline bulk of this material shows a first-order metal-insulator (MI) transition below the critical temperature. Although ρ(T) of all the as-grown films shows a semiconducting behavior at entire temperature range, an anomalous ρ(T) upturn with wide hysteresis can be clearly seen for the film grown on the SrLaAlO4 (SLAO) substrate, which applied the in-plane compressive stress to the film. Such anomaly in ρ(T) is interpreted as a sign of the first-order phase transition related with the spin-state (SS) transition, which was observed in the polycrystalline bulk.

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Section: -2mentioning

confidence: 99%

Electrical resistivity anomaly in (Pr1−yMy)1−xCaxCoO3 epitaxial films (M=Y, Gd) fabricated by pulsed laser deposition

et al. 2016

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“…The valence shift upon phase transition has been further confirmed and determined quantitatively by observation of the Pr 4+ related Schottky peak in heat capacity measurements [14] and by X-ray absorption spectroscopy at Pr L 3 edge [15,16]. In addition to the valence shift, a crossover from the IS or mixed LS/HS Co 3+ state to the LS states has been evidenced by drop of the paramagnetic susceptibility and by low values of effective moments below T MI , as well as by a detailed fit of the Co X-ray absorption and emission spectra [17].…”

Section: Introductionmentioning

confidence: 99%

Spin-state crossover and low-temperature magnetic state in yttrium-doped Pr0.7Ca0.3CoO3
Knı́žek
¹
,
Hejtmánek
²
,
Maryško
³

et al. 2013
Phys. Rev. B
19
1
13
0
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The structural and magnetic properties of two mixed-valence cobaltites with formal population of 0.30 Co 4+ ions per f.u., (Pr1−yYy)0.7Ca0.3CoO3 (y = 0 and 0.15), have been studied down to very low temperatures by means of the high-resolution neutron diffraction, SQUID magnetometry and heat capacity measurements. The results are interpreted within the scenario of the spin-state crossover from a room-temperature mixture of the intermediate spin Co3+ and low spin Co 4+ (IS/LS) at the to the LS/LS mixture in the sample ground states. In contrast to the yttrium free y = 0 that retains the metallic-like character and exhibits ferromagnetic ordering below 55 K, the doped system y = 0.15 undergoes a first-order metal-insulator transition at 132 K, during which not only the crossover to low spin states but also a partial electron transfer from Pr 3+ 4f to cobalt 3d states take place simultaneously. Taking into account the non-magnetic character of LS Co 3+ , such valence shift electronic transition causes a magnetic dilution, formally to 0.12 LS Co 4+ or 0.12 t2g hole spins per f.u., which is the reason for an insulating, highly non-uniform magnetic ground state without long-range order. Nevertheless, even in that case there exists a relatively strong molecular field distributed over all the crystal lattice. It is argued that the spontaneous FM order in y = 0 and the existence of strong FM correlations in y = 0.15 apparently contradict the single t2g band character of LS/LS phase. The explanation we suggest relies on a model of the defect induced, itinerant hole mediated magnetism, where the defects are identified with the magnetic high-spin Co 3+ species stabilized near oxygen vacancies.

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“…14 Still more recently, another XAS study performed in (Pr 0.7 Sm 0.3 ) 0.7 Ca 0.3 CoO 3  led us to consider that the achievement of a mixed LS/HS state above T* is the most likely option. 15 It is known that magnetization and heat capacity data can provide valuable complementary information, when dealing with the spin-state issue in cobalt oxides.…”

Section: G G E Tmentioning

confidence: 99%

Jumps in entropy and magnetic susceptibility at the valence and spin-state transition in a cobalt oxide

Hardy¹,

Guillou²,

Bréard³

2013

J. Phys.: Condens. Matter

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A wide family of cobalt oxides of formulation (Pr 1−y Ln y ) 1−x Ca x CoO 3 (Ln being a lanthanide) exhibits a coupled valence and spin-state transition (VSST) at a temperature T*, which involves two concomitant modifications: (i) a change in the spin state of Co 3+ from low-spin (T < T*) to a higher spin-state (T > T*), and (ii) a change in the valence state of Pr, from a mixed Pr 4+ /Pr 3+ state (T < T*) to a purely trivalent state (T > T*), accompanied by an equivalent charge transfer within the Co 3+ /Co 4+ subsystem. In the present paper, the VSST taking place in (Pr 0.7 Sm 0.3 ) 0.7 Ca 0.3 CoO 3 at T*  90 K is investigated by magnetization and heat capacity measurements. First , we quantitatively characterized the jumps in magnetic susceptibility () and entropy (S) around T*. Then, these values were compared to those calculated as a function of the variations in the population of the different cationic species involved in the VSST. X-ray absorption spectroscopy experiments recently showed that the higher spin state above T* should be regarded as an inhomogeneous mixture between lowspin (LS) and high-spin (HS) states. In the frame of this description, we demonstrate that the jumps in both  and S can be associated to the same change in the Co 3+ HS content around T*. This result lends further support to the relevance of the LS/HS picture for the VSST, challenging the currently dominant interpretation based on the occurrence of an intermediatespin (IS) state of Co 3+ above T*.

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Spin-state transition in Pr0.5Ca0.5CoO3analyzed by x-ray absorpt

Cited by 45 publications

References 40 publications

Electrical resistivity anomaly in (Pr1−yMy)1−xCaxCoO3 epitaxial films (M=Y, Gd) fabricated by pulsed laser deposition

Electrical resistivity anomaly in (Pr1−yMy)1−xCaxCoO3 epitaxial films (M=Y, Gd) fabricated by pulsed laser deposition

Spin-state crossover and low-temperature magnetic state in yttrium-doped Pr0.7Ca0.3CoO3
Knı́žek
¹
,
Hejtmánek
²
,
Maryško
³

et al. 2013
Phys. Rev. B
19
1
13
0
View full text Add to dashboard Cite

Jumps in entropy and magnetic susceptibility at the valence and spin-state transition in a cobalt oxide

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Spin-state transition in Pr0.5Ca0.5CoO3analyzed by x-ray absorpt

Cited by 45 publications

References 40 publications

Electrical resistivity anomaly in (Pr1−yMy)1−xCaxCoO3 epitaxial films (M=Y, Gd) fabricated by pulsed laser deposition

Electrical resistivity anomaly in (Pr1−yMy)1−xCaxCoO3 epitaxial films (M=Y, Gd) fabricated by pulsed laser deposition

Spin-state crossover and low-temperature magnetic state in yttrium-doped Pr0.7Ca0.3CoO3Knı́žek1, Hejtmánek2, Maryško3 et al. 2013Phys. Rev. B191130View full textAdd to dashboardCite

Jumps in entropy and magnetic susceptibility at the valence and spin-state transition in a cobalt oxide

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Spin-state crossover and low-temperature magnetic state in yttrium-doped Pr0.7Ca0.3CoO3
Knı́žek
¹
,
Hejtmánek
²
,
Maryško
³

et al. 2013
Phys. Rev. B
19
1
13
0
View full text Add to dashboard Cite