Comparative study of heterogeneous magnetic state above TC in La0.82Sr0.18CoO3 cobaltite and La0.83Sr0.17MnO3 manganite

Ryzhov, V. A.; Lazuta, A. V.; Molkanov, P. L.; Khavronin, V. P.; Курбаков, А. И.; Runov, V. V.; Mukovskiǐ, Ya. M.; Pestun, A.; Privezentsev, R.

doi:10.1016/j.jmmm.2012.02.059

Cited by 12 publications

(7 citation statements)

References 15 publications

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“…The long-range FM ordering in the cobaltites can be realized at an appropriate level of the doping due to the FM cluster percolation accompanied by the insulator-metal transition. Thus, this work confirmed the previous conclusion made in the comparative investigation of the LaSr pair of manganite-cobaltite [22]. The different character of the matrix magnetic properties in doped manganites and cobaltites may be a reason for the magnitude magnetoresistance in former at the same doping, as was briefly discussed in this work.…”

Section: Discussionsupporting

confidence: 91%

“…This suggests the growth of a cluster density without a noticeable change of parameters. Such a typical stage of the cluster evolution was also observed by us in other series of the hole-doped manganites (Nd 1−x Ba x MnO 3 , La 0.88 MnO x , La 1−x Sr x MnO 3 ), cobaltites (La 1−x Sr x CoO 3 ) [11][12][13][14][20][21][22] and in the LC02CO crystal discussed above. It can be attributed to a homogeneous nucleation of the FM clusters.…”

Section: Resultssupporting

confidence: 79%

“…At last, a comparative analysis of the FM cluster behavior was performed in La 0.82 Sr 0.18 CoO 3 and La 0.83 Sr 0.17 MnO 3 single crystals with a close level of doping by the same alkali-earth ion, in which I-M transitions were detected near T C [22]. In these compounds two first stages of the clustered state formation displayed the same character, whereas the third stages essentially differed.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic phase transition and clustered state in Ca-doped lanthanum cobaltite and manganite with insulator ground states

Ryzhov¹,

Lazuta²,

Khavronin³

et al. 2014

J. Phys.: Condens. Matter

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The transport and magnetic properties (ac linear and nonlinear (second and third orders) susceptibilities) are presented for La0.8Ca0.2MnO3 and La0.8Ca0.2CoO3 single crystals with insulator ground states. The ferromagnetic (FM) clusters with similar magnetic characteristics originate in the paramagnetic phases of both compounds below some temperature T(∗). At high temperatures the FM clusters arise at the preferable sites that can be attributed to the chemical inhomogeneities, their density being weakly T-dependent. On cooling a homogeneous nucleation of the FM clusters develops below a definite temperature T(#) that is characterized by a fast growth of their density. These two stages are observed in both compounds. At the third stage a coalescence of the FM clusters starts in the doped cobaltite, whereas in the manganite the development of matrix FM ordering occurs which changes a cluster's behavior. The indicated features support the common nature of the cluster state in the doped cobaltite and manganite. The difference in their evolution is a consequence of the different magnetic properties of the matrices in the manganite and cobaltite.

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Section: Discussionsupporting

confidence: 91%

Section: Resultssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Magnetic phase transition and clustered state in Ca-doped lanthanum cobaltite and manganite with insulator ground states

Ryzhov¹,

Lazuta²,

Khavronin³

et al. 2014

J. Phys.: Condens. Matter

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“…These features correspond to M 2 response of ensemble of MNPs in the single domain state (Figure 3). 27 A weak field hysteresis is predictive for a close to SPM regime, which is in accordance with a single domain structure. M 2 responses yielded by the Fe 3 O 4 nuclei and magnetic parameters of the latter in the first approximation are not affected by the formation of the hybrid dextran-chitosan shell.…”

Section: Results Synthesized Cs-dx-spions Exhibit High-contrast-enhansupporting

confidence: 65%

Targeting experimental orthotopic glioblastoma with chitosan-based superparamagnetic iron oxide nanoparticles (CS-DX-SPIONs)

Shevtsov¹,

Nikolaev²,

Marchenko³

et al. 2018

IJN

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BackgroundGlioblastoma is the most devastating primary brain tumor of the central nervous system in adults. Magnetic nanocarriers may help not only for a targeted delivery of chemotherapeutic agents into the tumor site but also provide contrast enhancing properties for diagnostics using magnetic resonance imaging (MRI).MethodsSynthesized hybrid chitosan-dextran superparamagnetic nanoparticles (CS-DX-SPIONs) were characterized using transmission electron microscopy (TEM) and relaxometry studies. Nonlinear magnetic response measurements were employed for confirming the superparamagnetic state of particles. Following in vitro analysis of nanoparticles cellular uptake tumor targeting was assessed in the model of the orthotopic glioma in rodents.ResultsCS-DX-SPIONs nanoparticles showed a uniform diameter of 55 nm under TEM and superparamagentic characteristics as determined by T1 (spin-lattice relaxation time) and T2 (spin-spin relaxation time) proton relaxation times. Application of the chitosan increased the charge from +8.9 to +19.3 mV of the dextran-based SPIONs. The nonlinear magnetic response at second harmonic of CS-DX-SPIONs following the slow change of stationary magnetic fields with very low hysteresis evidenced superparamagnetic state of particles at ambient temperatures. Confocal microscopy and flow cytometry studies showed an enhanced internalization of the chitosan-based nanoparticles in U87, C6 glioma and HeLa cells as compared to dextran-coated particles. Cytotoxicity assay demonstrated acceptable toxicity profile of the synthesized nanoparticles up to a concentration of 10 μg/ml. Intravenously administered CS-DX-SPIONs in orthotopic C6 gliomas in rats accumulated in the tumor site as shown by high-resolution MRI (11.0 T). Retention of nanoparticles resulted in a significant contrast enhancement of the tumor image that was accompanied with a dramatic drop in T2 values (P<0.001). Subsequent histological studies proved the accumulation of the nanoparticles inside glioblastoma cells.ConclusionHybrid chitosan-dextran magnetic particles demonstrated high MR contrast enhancing properties for the delineation of the brain tumor. Due to a significant retention of the particles in the tumor an application of the CS-DX-SPIONs could not only improve the tumor imaging but also could allow a targeted delivery of chemotherapeutic agents.

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“…The MEPS occurs in manganites, as well, revealing a certain resemblance to that in cobaltites at a close level of doping, in compounds both conserving their insulator state and exhibiting insulator-metal transition below the Curie temperature [14 and 15]. In manganites, however, the increase of paramagnetic fluctuations upon cooling resulting in the FM phase transition impedes and restricts in temperature observation of FM clusters [14]. The latter is easier for cobaltites as their matrix is only slightly paramagnetic down to lower temperatures.…”

Section: Introductionmentioning

confidence: 99%

Temperature evolution of superparamagnetic clusters in single-crystal La0.85Sr0.15CoO3 from nonlinear magnetic ac response and neutron depolarization

Lazuta,

Ryzhov,

Runov

et al. 2015

Preprint

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The representative measurements of the second harmonic in ac magnetization complemented by neutron depolarization have been performed for single-crystal La0.85Sr0.15CoO3 in the temperature range 97 K< T < 230 K, where occurrence of a small fraction ( 10 −3 ) of nanoscale ferromagnetic clusters (FMC) has been found. Magnetic, geometrical and dynamical parameters of the FMC system have been evaluated in the temperature range T < 140 K, where superparamagnetic regime installs, by means of the formalism involving the Fokker-Planck equation (FPE). With lowering the temperature, the amount of clusters fraction, the cluster size and magnetic moment along with its diffusion relaxation time strongly increase, each in its own temperature interval. Below 130 K, FMC contribute essentially to the total linear magnetic susceptibility. The damping factor of the order 10 −1 proves the importance of precession in thermal relaxation of the cluster magnetic moment. The FMC are a precursor of long-range ferromagnetic correlations seen below 100 K with neutron-scattering techniques. The employed technique supplemented with FPE-based datatreatment formalism is a novel method for studying superparamagnetic systems.

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Comparative study of heterogeneous magnetic state above TC in La0.82Sr0.18CoO3 cobaltite and La0.83Sr0.17MnO3 manganite

Cited by 12 publications

References 15 publications

Magnetic phase transition and clustered state in Ca-doped lanthanum cobaltite and manganite with insulator ground states

Magnetic phase transition and clustered state in Ca-doped lanthanum cobaltite and manganite with insulator ground states

Targeting experimental orthotopic glioblastoma with chitosan-based superparamagnetic iron oxide nanoparticles (CS-DX-SPIONs)

Temperature evolution of superparamagnetic clusters in single-crystal La0.85Sr0.15CoO3 from nonlinear magnetic ac response and neutron depolarization

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