Magnetotransport properties of La 1−x Ca x MnO 3 (0.52 ≤ x ≤ 0.75): Signature of phase coexistence

Čulo, Matija; Basletić, Mario; Tafra, Emil; Hamzić, Amir; Tomić, Silvia; Fischgrabe, Florian; Moshnyaga, V.; Korin-Hamzić, Bojana

doi:10.1016/j.tsf.2017.04.027

Cited by 10 publications

(9 citation statements)

References 46 publications

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“…We focus on the very boundary between the FM metallic and CO/AFM insulating phases x = 0.5, where the grain size is known to have a large impact on the stability of the CO/AFM phase [46][47][48][49][50][51][52]. Our results show the presence of the 3D VRH in accordance with the thin film study [45] and the coexistence of both FM and CO/AFM phases. Reducing the grain size leads to the suppression of the CO/AFM state and a growth of the FM contribution.…”

Section: Introductionsupporting

confidence: 80%

“…To gain insight into the origin of the insulating behavior in manganites, we recently focused on the poorly explored insulating CO/AFM part of the phase diagram x > 0.5 (Figure 1a). Our study on La 1−x Ca x MnO 3 thin films indicated that dc resistivity follows the Mott three-dimensional (3D) variable-range-hopping(VRH) mechanism, which implies the crucial role of structural disorder in driving the insulating behavior through the Anderson localization of conducting e g electrons [45]. To further explore these ideas, here we conduct a dc transport and magnetization study on polycrystalline (ceramic) La 1−x Ca x MnO 3 samples, where the level of structural disorder can be controlled by the grain size.…”

Section: Introductionmentioning

confidence: 87%

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Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3

et al. 2022

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Among transition metal oxides, manganites have attracted significant attention because of colossal magnetoresistance (CMR)—a magnetic field-induced metal–insulator transition close to the Curie temperature. CMR is closely related to the ferromagnetic (FM) metallic phase which strongly competes with the antiferromagnetic (AFM) charge ordered (CO) phase, where conducting electrons localize and create a long range order giving rise to insulator-like behavior. One of the major open questions in manganites is the exact origin of this insulating behavior. Here we report a dc resistivity and magnetization study on manganite La1−xCaxMnO3 ceramic samples with different grain size, at the very boundary between CO/AFM insulating and FM metallic phases x=0.5. Clear signatures of variable range hopping (VRH) are discerned in resistivity, implying the disorder-induced (Anderson) localization of conducting electrons. A significant increase of disorder associated with the reduction in grain size, however, pushes the system in the opposite direction from the Anderson localization scenario, resulting in a drastic decrease of resistivity, collapse of the VRH, suppression of the CO/AFM phase and growth of an FM contribution. These contradictory results are interpreted within the standard core-shell model and recent theories of Anderson localization of interacting particles.

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Section: Introductionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 87%

Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3

et al. 2022

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“…In particular, a negative magnetoresistance has been observed in many materials, see e.g. [39,40,41,42,43,44,45,46]. Interestingly, one finds from Figure 8 that our system also exhibits negative magnetoresistance 11 .…”

Section: Dyonic Solutions and Negative Magnetoresistancesupporting

confidence: 55%

Backreacted DBI magnetotransport with momentum dissipation

Cremonini

Hoover

2017

J. High Energ. Phys.

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We examine magnetotransport in a holographic Dirac-Born-Infeld model, taking into account the effects of backreaction on the geometry. The theory we consider includes axionic scalars, introduced to break translational symmetry and generate momentum dissipation. The generic structure of the DC conductivity matrix for these theories is extremely rich, and is significantly more complex than that obtained in the probe approximation. We find new classes of black brane solutions, including geometries that exhibit Lifshitz scaling and hyperscaling violation, and examine their implications on the transport properties of the system. Depending on the choice of theory parameters, these backgrounds can lead to metallic or insulating behavior. Negative magnetoresistance is observed in a family of dynoic solutions. Some of the new backreacted geometries also support magneticfield-induced metal-insulator transitions.

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“…As we can see, the La 0.5 Ca 0.5 MnO 3 ceramic sample with the largest grains (4000 nm) shows a clear maximum in dlnρ/dln(1/T) at ≈ 200 K. Such a maximum in dlnρ/dln(1/T) is typical for La 1−x Ca x MnO 3 compounds in the CO/AFM insulating part of phase diagram x ≥ 0.5, and as shown in Refs. [99,100], its position agrees well with the temperature at which the CO transition is expected to occur according to the phase diagram. The maximum in dlnρ/dln(1/T) at ≈ 200 K in Figure 8b shows a fair agreement with the phase diagram as well.…”

Section: La 05 Ca 05 Mnosupporting

confidence: 75%

Charge Transport in the Presence of Correlations and Disorder: Organic Conductors and Manganites

Tafra,

Basletić,

Ivek

et al. 2024

Materials

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One of the most fascinating aspects of condensed matter is its ability to conduct electricity, which is particularly pronounced in conventional metals such as copper or silver. Such behavior stems from a strong tendency of valence electrons to delocalize in a periodic potential created by ions in the crystal lattice of a given material. In many advanced materials, however, this basic delocalization process of the valence electrons competes with various processes that tend to localize these very same valence electrons, thus driving the insulating behavior. The two such most important processes are the Mott localization, driven by strong correlation effects among the valence electrons, and the Anderson localization, driven by the interaction of the valence electrons with a strong disorder potential. These two localization processes are almost exclusively considered separately from both an experimental and a theoretical standpoint. Here, we offer an overview of our long-standing research on selected organic conductors and manganites, that clearly show the presence of both these localization processes. We discuss these results within existing theories of Mott–Anderson localization and argue that such behavior could be a common feature of many advanced materials.

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Magnetotransport properties of La 1−x Ca x MnO 3 (0.52 ≤ x ≤ 0.75): Signature of phase coexistence

Abstract: We report the temperature and magnetic field dependence of transport properties in epitaxial films of the manganite La 1−x Ca x MnO 3 in the overdoped region of the phase diagram for x > 0.5, where a charge-

Cited by 10 publications

References 46 publications

Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3

Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3

Backreacted DBI magnetotransport with momentum dissipation

Charge Transport in the Presence of Correlations and Disorder: Organic Conductors and Manganites

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