Nanoscale phase separation in manganites

Kagan, M. Yu.; Klaptsov, A. V.; Brodsky, I. V.; Кugel, K. I.; Sboychakov, A. O.; Rakhmanov, A. L.

doi:10.1088/0305-4470/36/35/304

Cited by 36 publications

(16 citation statements)

References 35 publications

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“…The ferromagnetic clusters may coexist with the nonferromagnetic regions and the whole system can be thought of a magnetically phase segregated state of a manganite. This kind of phase separation in terms of existence of ferromagnetic regions inside antiferromagnetic matrix was also theoretically predicted by Kagan et al [24] in low doped manganites. Rivadulla et al [25] experimentally showed the possibility of formation of such a state in manganites where frustration and glassiness may arise due to inter-cluster interaction.…”

Section: Resultssupporting

confidence: 77%

Probing the magnetic state by linear and non-linear ac magnetic susceptibility measurements in under-doped manganite Nd0.8Sr0.2MnO3

Kundu

Nath

2010

Journal of Magnetism and Magnetic Materials

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a b s t r a c tWe have thoroughly investigated the entire magnetic states of under-doped ferromagnetic-insulating manganite Nd 0.8 Sr 0.2 MnO 3 through temperature-dependent linear and non-linear complex ac magnetic susceptibility measurements. This ferromagnetic-insulating manganite is found to have frequencyindependent ferromagnetic to paramagnetic transition temperature at around 140 K. At around 90 K (E T e ) the sample shows a second frequency-dependent re-entrant magnetic transition as explored through complex ac susceptibility measurements. Non-linear ac susceptibility measurements (higher harmonics of ac susceptibility) have also been performed (with and without the superposition of a dc magnetic field) to further investigate the origin of this frequency dependence (dynamic behavior at this re-entrant magnetic transition). Divergence of 3rd harmonic of ac susceptibility in the limit of zero exciting field indicates a spin-glass-like freezing phenomena. However, large value of spin-relaxation time (t 0 =10 À 8 s) and small value of coercivity ($ 22 Oe) obtained at low temperature (below T e ) from critical slowing down model and dc magnetic measurements, respectively, are in contrast with what generally observed in a canonical spin glass (t 0 =10 À 12 -10 À 14 s and very large value of coercivity below freezing temperature). We have attributed our observation to the formation of finite size ferromagnetic clusters which are formed as consequence of intrinsic phase separation and undergo cluster glass-like freezing below certain temperature in this under-doped manganite. The results are supported by the electronic-and magneto-transport data.

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Section: Resultssupporting

confidence: 77%

Probing the magnetic state by linear and non-linear ac magnetic susceptibility measurements in under-doped manganite Nd0.8Sr0.2MnO3

Kundu

Nath

2010

Journal of Magnetism and Magnetic Materials

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“…few electrons [30], and for the 1D paramagnet at higher temperatures [31]. Small ferromagnetic droplets were predicted from energy considerations [32].…”

Section: Introductionmentioning

confidence: 94%

Polaronic aspects of the two-dimensional ferromagnetic Kondo model

Daghofer

Koller

Evertz

et al. 2004

J. Phys.: Condens. Matter

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Abstract. The two-dimensional ferromagnetic Kondo model with classical corespins is studied via unbiased Monte Carlo simulations for a hole doping up to x = 12.5%. A canonical algorithm for finite temperatures is developed. We show that with realistic parameters for the manganites and at low temperatures, the double-exchange mechanism does not lead to phase separation on a twodimensional lattice but rather stabilises individual ferromagnetic polarons for this doping range. A detailed analysis of unbiased Monte Carlo results reveals that the polarons can be treated as independent particles for these hole concentrations. It is found that a simple polaron model describes the physics of the ferromagnetic Kondo model amazingly well. The ferromagnetic polaron picture provides an obvious explanation for the pseudogap in the one-particle spectral function A k (ω) observed in the ferromagnetic Kondo model.

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“…very few electrons) for S = 1/2 core spins [28,29], for the 1D AF Kondo model with few electrons [30], and for the 1D paramagnet at higher temperatures [31]. Small ferromagnetic droplets were predicted from energy considerations [32].…”

mentioning

confidence: 92%

New recommended values of the fundamental physical constants (CODATA 2006)

Karshenboim

2008

Phys.-Usp.

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The two-dimensional ferromagnetic Kondo model with classical core spins is studied via unbiased Monte Carlo simulations for a hole doping up to x = 12.5%. A canonical algorithm for finite temperatures is developed. We show that, with realistic parameters for the manganites and at low temperatures, the double-exchange mechanism does not lead to phase separation on a twodimensional lattice but rather stabilizes individual ferromagnetic polarons for this doping range. A detailed analysis of unbiased Monte Carlo results reveals that the polarons can be treated as independent particles for these hole concentrations. It is found that a simple polaron model describes the physics of the ferromagnetic Kondo model amazingly well. The ferromagnetic polaron picture provides an obvious explanation for the pseudogap in the one-particle spectral function A k (ω) observed in the ferromagnetic Kondo model.

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Nanoscale phase separation in manganites

Cited by 36 publications

References 35 publications

Probing the magnetic state by linear and non-linear ac magnetic susceptibility measurements in under-doped manganite Nd0.8Sr0.2MnO3

Probing the magnetic state by linear and non-linear ac magnetic susceptibility measurements in under-doped manganite Nd0.8Sr0.2MnO3

Polaronic aspects of the two-dimensional ferromagnetic Kondo model

New recommended values of the fundamental physical constants (CODATA 2006)

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