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Chechersky, Vladimir; Nath, Amar; Michel, C.; Hervieu, M.; Ghosh, K.; Greene, R. L.

doi:10.1103/physrevb.62.5316

Cited by 41 publications

(19 citation statements)

References 14 publications

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“…Similar observations were made by Podzorov et al [37] and Zhang et al [38]. In this compound, apart from two ferromagnetic phases [39,40], we also detect nano size magnetic clusters well below T C [39] which can help to understand the observations made by the above mentioned researches.…”

Section: Influence Of External Magnetic Fieldsupporting

confidence: 90%

“…Taking into consideration the superparamagnetic-like behavior of mixed valence manganites at different temperatures [22][23][24][25][26][27][28][29]39] and the interaction energy between a modest H ext and the nano spin clusters (Fig. 3), we estimate approximately the average size of the magnetic clusters as roughly 20 Å in diameter (if approximated by a sphere) containing couple of hundred Mn 3+ /Mn 4+ atoms.…”

Section: Influence Of External Magnetic Fieldmentioning

confidence: 99%

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Anomalous magnetic and dynamic behavior in magnetoresistive compounds: origin of bulk colossal magnetoresistivity

Chechersky

Nath

2002

Low Temperature Physics

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We present the results of our extensive Mössbauer effect studies carried out on a wide variety of mixed valence manganites as well as other types of magnetoresistive materials, including pyrochlore Tl 2 Mn 2 O 7 and the chalcospinels Fe 0.5 Cu 0.5 Cr 2 S 4 and FeCr 2 S 4 with absolutely different nature of magnetism, in a search for similarities linked to their magnetoresistive behavior. Double exchange electron transfer and coupling between the electrons and Jahn-Teller lattice distortions invoked by most theories to explain colossal magnetoresistivity and associated metal-insulator transition in manganites are not applicable neither to pyrochlore nor to chalcospinels. Nevertheless, we find intriguing similarities in anomalous magnetic and dynamic behavior among these widely different systems at, above and below the Curie temperature T C , which shed light on the origin of bulk magnetoresistivity in general. All these compounds share the following features. The long range ferromagnetic order breaks down even below the Curie temperature with the formation of nano size spin clusters. Softening of lattice was observed near T C . The short range interactions in these spin clusters survive well above T C . When an external magnetic field is applied, the spin clusters coalesce to form large clusters with considerable lowering of resistivity. There is a strong evidence that the existence of nano size spin clusters with superparamagnetic-like behavior near T C is a prerequisite to occurrence of bulk magnetoresistity. PACS: 76.80.+yIn honor of V.V. Eremenko

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Section: Influence Of External Magnetic Fieldsupporting

confidence: 90%

Section: Influence Of External Magnetic Fieldmentioning

confidence: 99%

Anomalous magnetic and dynamic behavior in magnetoresistive compounds: origin of bulk colossal magnetoresistivity

Chechersky

Nath

2002

Low Temperature Physics

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“…Scaling plots based on the measurement of magnetic isotherms near the critical temperature have been used in order to derive the critical exponents and verify the second order type of the transition [2,3]. Using 57 Fe Mössbauer spectroscopy, it was found recently that the ferromagnetic (FM) metallic phase in La 1−x Ca x MnO 3 (x∼0.3) has a rather complex character, since at least two spatially separated FM regions exist, which possess temperature-dependent volumes and different internal hyperfine fields [4]. The long-range ferromagnetic ordering breaks down into small magnetic clusters exhibiting superparamagneticlike behavior below T c .…”

Section: Introductionmentioning

confidence: 99%

Critical behavior of La0.67−y (Sr, Ba, Ca)0.33+y Mn1−x Sn x O3 (x = 0.01, 0.02, y = 0, 0.07) perovskites

et al. 2006

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“…3 Last decade, the formation of inhomogeneous states, referred as phase separation, was discovered in doped La 1-x (Ca,Sr) x MnO 3 manganites. There was observed with muon spin relaxation measurements, 4 Mössbauer spectroscopy 5 and nuclear magnetic resonance (NMR) 6 that ferromagnetic phase is inhomogeneous and decomposes into at least two ferromagnetic phases. The phases are characterized by different DE interaction, magnetic Zeeman splitting, rate of hopping of electron holes among the Mn 3þ /Mn 4þ sites, etc.…”

Section: Introductionmentioning

confidence: 99%

Local structure and magnetic inhomogeneity of nano-sized La0.7Sr0.3MnO3 manganites

Ulyanov

Yang

Mazur

et al. 2011

Journal of Applied Physics

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We present the study of the local structure and magnetic inhomogeneity of nano-sized La0.7Sr0.3MnO3 manganites performed by x-ray absorption fine structure (XAFS) spectroscopy and nuclear magnetic resonance (NMR). Nano-powders with particle size of 50–200 nm (NP1) and 20 nm (NP2), and bulk samples (BS) were studied. EXAFS data show the difference between the local structure of core and outer shell of the nano-particle. The data evidenced that the shell of particles presents the disordered crystalline array. According to the NMR, at low temperature the magnetic state of NP1 sample is homogenous. However, with increase of temperature the two ferromagnetic phases, with strong and weakened double exchange, coexist. The NP2 powder is magnetically homogeneous and characterized by weakened double exchange at all temperatures of the existence of the magneto-ordered state. The results specify on possible existence of characteristic spatial scale below which the phase stratification becomes energetically unfavorable.

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Emission Mössbauer study of the electronic phases inLa0.7Ca0.3MnO

Cited by 41 publications

References 14 publications

Anomalous magnetic and dynamic behavior in magnetoresistive compounds: origin of bulk colossal magnetoresistivity

Anomalous magnetic and dynamic behavior in magnetoresistive compounds: origin of bulk colossal magnetoresistivity

Critical behavior of La0.67−y (Sr, Ba, Ca)0.33+y Mn1−x Sn x O3 (x = 0.01, 0.02, y = 0, 0.07) perovskites

Local structure and magnetic inhomogeneity of nano-sized La0.7Sr0.3MnO3 manganites

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