Relaxation nature of a current settling upon the application of an electric voltage in LaMnO3 crystals

Gubkin, M. K.; Perekalina, T. M.; Balbashov, A. M.; Kireev, V. V.; Pushko, S. V.

doi:10.1134/1.1349479

Cited by 6 publications

(8 citation statements)

References 11 publications

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“…They found for phases of nominal composition La \V A V MnO (A"Na, K, Rb) that up to 40% of the La could be replaced by K but only to 20% if Na or Rb were used. Gubkin et al, reported on the high-temperature solution growth of La Na MnO single crystals with ¹ /¹ '+ close to 300 K and MR &30% (H"2 T ) near ¹ /¹ '+ (21). Alkali-metalsubstituted systems, similar to those in Ref.…”

Section: Introductionsupporting

confidence: 62%

Synthesis and Properties of Lanthanum Sodium Manganate Perovskites Crystals

McCarroll

Fawcett

Greenblatt

et al. 1999

Journal of Solid State Chemistry

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Section: Introductionsupporting

confidence: 62%

Synthesis and Properties of Lanthanum Sodium Manganate Perovskites Crystals

McCarroll

Fawcett

Greenblatt

et al. 1999

Journal of Solid State Chemistry

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“…I, Smolenskii et al 12 and Gubkin et al 13 proposed that the dielectric relaxation peak observed in Bi doped STO was a ferroelectric nature with the ''diffuse phase transition'' ͑currently used term is ''relaxor ferroelectric''͒. This is the case for mode C. However, an alternative explanation is necessary for modes A and B occurring in the low level Bi doped STO.…”

Section: Comments On the Interpretations Of Smolenskii And Skanavi Onmentioning

confidence: 99%

“…[3][4][5][6][7][8][9][10] The explanation of dielectric permittivity peaks is rather controversial, which ranges from dipolar glass behavior to a domain state, and to the occurrence of ferroelectricity. [3][4][5][6][7][8][9][10][11][12][13] Skanavi et al 11 reported that a high permittivity peak with frequency dispersion is induced by Bi doping in STO. They suggested a polarization mechanism of ''hopping ions,'' rather than the occurrence of ferroelectricity.…”

Section: Introductionmentioning

confidence: 99%

“…They suggested a polarization mechanism of ''hopping ions,'' rather than the occurrence of ferroelectricity. However, based on the observation of the slim electric hysteresis loop in Bi doped STO, Smolenskii et al 12 and Gubkin et al 13 suggested a ferroelectric mechanism with a so-called ''diffuse phase transition.' ' Recently, in a systematic study in Bi doped STO, the present authors 14 -18 observed the coexistence of several di-electric peaks with different physical characteristics in Bi doped STO, and, with increasing Bi concentration, some of them disappeared.…”

Section: Introductionmentioning

confidence: 99%

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Dielectric relaxor and ferroelectric relaxor: Bi-doped paraelectric SrTiO3

Chen¹,

Yu²

2002

Journal of Applied Physics

131

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Articles you may be interested inUnification of the negative electrocaloric effect in Bi1/2Na1/2TiO3-BaTiO3 solid solutions by Ba1/2Sr1/2TiO3 doping J.The dielectric relaxation behavior of (Na0.82K0.18)0.5Bi0.5TiO3 ferroelectric thin filmIn this article, we report the evolution of the dielectric behavior from a dielectric relaxor to a ferroelectric relaxor with variation of Bi concentration in (Sr 1Ϫ1.5x Bi x )TiO 3 (0рxр0.2). In the doping range 0.0005рxр0.002, two dielectric modes A and B are induced. The temperature (T m ) where the permittivity maximum occurs for modes A and B is independent of Bi concentration and of dc electric fields. The complex permittivity of modes A and B follows the empirical Cole-Cole equation. The relaxation time for modes A and B follows the Arrhenius law. The dielectric possessing this type of dielectric behavior is named as a ''dielectric relaxor.'' At xу0.0033, an additional mode C appears, whose T m increases with increasing Bi concentration. The complex permittivity for mode C does not follow the Cole-Cole equation. The relaxation time of mode C follows the Vogel-Fulcher law, indicating typical relaxor-ferroelectric behavior. In this work, we refer it to a ''ferroelectric relaxor'' mode. In the range of 0.0033рxр0.133, the coexistence of the dielectric-relaxor modes and the ferroelectric-relaxor mode is observed. In the samples doped with higher Bi concentration, modes A and B gradually merge into mode C, and only ferroelectric-relaxor behavior remains at xу0.133. This system provides a composition-controlled example of evolution from a ''dielectric relaxor'' to a ''ferroelectric relaxor.'' In addition, some controversial interpretations of the dielectric behavior of the Bi doped SrTiO 3 solid solutions in the literature are discussed, and the polarization relaxation species of modes A and B are attributed to Bi ions.

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“…Indeed a high TMR ratio well above 100% has been achieved at low temperatures and low applied fields H of the order of 10 mT [4,5]. In addition to planar type tunnel junctions, a large low field magnetoresistance was found for grain boundaries (GBs) in the perovskite manganites [6,7,8,9,10,11]. In contrast to the colossal magnetoresistance (CMR) observed in single crystals, the GB magnetoresistance can be observed at low H (∼ 10 mT) and over the entire temperature range below the Curie temperature T C .…”

mentioning

confidence: 97%

Voltage and temperature dependence of the grain boundary tunneling magnetoresistance in manganites

Hoefener¹,

Philipp²,

Klein³

et al. 2000

Europhys. Lett.

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Abstract. -We have performed a systematic analysis of the voltage and temperature dependence of the tunneling magnetoresistance (TMR) of grain boundaries (GB) in the manganites. We find a strong decrease of the TMR with increasing voltage and temperature. The decrease of the TMR with increasing voltage scales with an increase of the inelastic tunneling current due to multi-step inelastic tunneling via localized defect states in the tunneling barrier. This behavior can be described within a three-current model for magnetic tunnel junctions that extends the two-current Jullière model by adding an inelastic, spin-independent tunneling contribution. Our analysis gives strong evidence that the observed drastic decrease of the GB-TMR in manganites is caused by an imperfect tunneling barrier.The tunneling resistance between two ferromagnetic metal layers separated by a thin insulating barrier depends on the relative orientation of the magnetization and the electron spin polarization in each layer [1]. Since for materials with large spin polarization a large tunneling magnetoresistance (TMR) can be achieved, magnetic tunnel junctions have recently attracted much attention and their use in memory devices in envisaged [2,3]. Due to their half-metallic ferromagnetic state with only a single spin band crossing the Fermi level, the spin polarization of the perovskite manganites of composition La 2/3 D 1/3 MnO 3 with D = Ca, Sr, and Ba is close to 100%. According to the Jullière model[1], a high TMR ratio ∆R/R = (R ↑↓ − R ↑↑ )/R ↑↑ = (2P 1 P 2 )/(1 − P 1 P 2 ) is expected making these materials attractive for magnetic tunnel junctions. Here, R ↑↑ and R ↑↓ is the tunneling resistance for parallel and anti-parallel magnetization orientation and P i = 2a i − 1 is the spin polarization where a i is the fraction of majority spin electrons in the density of states of layer i. Indeed a high TMR ratio well above 100% has been achieved at low temperatures and low applied fields H of the order of 10 mT [4,5]. In addition to planar type tunnel junctions, a large low field magnetoresistance was found for grain boundaries (GBs) in the perovskite manganites Typeset using EURO-T E X

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Relaxation nature of a current settling upon the application of an electric voltage in LaMnO3 crystals

Cited by 6 publications

References 11 publications

Synthesis and Properties of Lanthanum Sodium Manganate Perovskites Crystals

Synthesis and Properties of Lanthanum Sodium Manganate Perovskites Crystals

Dielectric relaxor and ferroelectric relaxor: Bi-doped paraelectric SrTiO3

Voltage and temperature dependence of the grain boundary tunneling magnetoresistance in manganites

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