Conductivity noise across temperature-driven transitions of rare-earth nickelate heterostructures

Daptary, Gopi Nath; Kumar, Siddharth; Kareev, M.; Chakhalian, Jak; Bid, Aveek; Middey, S.

doi:10.1103/physrevb.100.125105

Cited by 10 publications

(9 citation statements)

References 54 publications

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“…The peak in the dðlog RÞ=dð1=TÞ curve gives the critical temperature for N eel transition T h N $ 149 K in heating run. [2][3][4]14 A similar analysis yields T c N $ 138 K for cooling run (data not shown). From the preliminary electron transport characterization, we observe that the film is in an antiferromagnetic insulator (AFI) phase at low temperature [pink-shaded region in Fig.…”

supporting

confidence: 52%

“…Rare-earth nickelates (RNiO 3 ) are of great current research interest as many exciting phenomena, such as metal-insulator transition, charge ordering, spin density wave, N eel transition, charge disproportionation, and structural transformation, have been predicted and experimentally observed in this systems. [1][2][3][4][5][6] With varying temperature, these oxides generally undergo a structural transition, inducing an electronic charge ordering and a consequent metal-insulator transition. 1,4,[7][8][9] The nature of this insulating ground state is under intense debate.…”

mentioning

confidence: 99%

“…The presence of RTN indicates that in this T-range, the system coexists in two distinct phases, as previously reported for NdNiO 3 and EuNiO 3 systems. 2,4 We elaborate on the origin of this mixed electronic phase below.…”

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confidence: 99%

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Resistance fluctuation spectroscopy of phase transitions in (La0.2Pr0.2Nd0.2Sm0.2Eu0.2)NiO3 thin films

Nagarajan

Patel

Bid

2023

Applied Physics Letters

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The study of phase transitions is crucial to understanding the physics of materials and utilizing them for technological applications. This article presents a detailed analysis of the electronic transport properties of high entropy oxide thin films. We observe an increase in resistance fluctuations across a first-order phase transition. We show that the noise arises from an electronic phase separation accompanying the spin ordering due to the formation of domains of localized and delocalized charges. We conclude that due to charge disproportionation, the charge carriers form domains of localized and delocalized electrons in this system. Our study establishes the existence of multiple states with near equal energy in such complex oxide thin films.

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confidence: 52%

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confidence: 99%

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Resistance fluctuation spectroscopy of phase transitions in (La0.2Pr0.2Nd0.2Sm0.2Eu0.2)NiO3 thin films

Nagarajan

Patel

Bid

2023

Applied Physics Letters

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“…However, the microscopic details e.g. nucleation of insulating/metallic phase around the transition temperature 50 , charge transfer between Ni and RE sites 51 , conductivity noise 52 , etc. may depend on the on the details of RE composition and needs to be explored further.…”

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confidence: 99%

Epitaxial stabilization of ultra thin films of high entropy perovskite

Patel

Ojha

Kumar

et al. 2020

Applied Physics Letters

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High entropy oxides (HEOs) are a class of materials, containing equimolar portions of five or more transition metal and/or rare-earth elements. We report here about the layer-by-layer growth of HEO [(La 0.2 Pr 0.2 Nd 0.2 Sm 0.2 Eu 0.2 )NiO 3 ] thin films on NdGaO 3 substrates by pulsed laser deposition. The combined characterizations with in-situ reflection high energy electron diffraction, atomic force microscopy, and X-ray diffraction affirm the single crystalline nature of the film with smooth surface morphology. The desired +3 oxidation of Ni has been confirmed by an element sensitive X-ray absorption spectroscopy measurement. Temperature dependent electrical transport measurements revealed a first order metal-insulator transition with the transition temperature very similar to the undoped NdNiO 3 . Since both of these systems have a comparable tolerance factor, this work demonstrates that the electronic behaviors of A-site disordered perovskite-HEOs are primarily controlled by the average tolerance factor.Finding new materials and new ways to tune material's properties are essential to fulfill the demand of the constantly evolving modern technology. Transition metal oxides show various fascinating electronic and magnetic phenomena such as metal-insulator transition, superconductivity, colossal magnetoresistance, multiferroicity, skyrmions, etc., which have lots of prospect for technological applications 1-6 . Furthermore, transition metal (TM) based high entropy oxides (HEOs) are being explored in recent years to achieve tunable properties in unexplored parts of complex phase diagram 7-21 . In general, the configurational entropy of a multi-component solid solution can be enhanced by mixing a large number of cations in equiatomic proportions and a single structural phase is formed if the entropy contribution overcomes enthalpy driven phase separation (∆G mix =∆H mix -T ∆S mix ; ∆G mix , ∆H mix , ∆S mix are Gibbs free energy, enthalpy and entropy of mixing, respectively) 7,18 . After the report of the first HEO [Mg 0.2 Ni 0.2 Co 0.2 Cu 0.2 Zn 0.2 O with rocksalt structure] by Rost et al. 7 , HEOs with other structural symmetry such as perovskite 15,17 , spinel 16 have been also synthesized. However, this promising field of HEO is at a very early stage and most of the aspects of HEOs are yet to be explored experimentally. For example, it is still unknown whether the strong disorder or the average tolerance factor (t avg ) determines the electronic and magnetic behaviors of perovskite-HEOs.As a prototypical example of perovskite (ABO 3 ) series, RENiO 3 (RE= La, Pr, Nd, Sm, Eu...Lu) exhibits an interesting phase diagram as a function of tolerance factor (t= R RE +RO √ 2(RNi+RO) , where R RE , R Ni , R O are radii of RE, Ni and O, respectively) 22,23 . LaNiO 3 , the least distorted member of this series remains metallic and paramagnetic down to the lowest temperature. Bulk PrNiO 3 and NdNiO 3 (NNO) show temperature driven simultaneous transitions from an orthorhombic, paramagnetic, metallic phase to a monoclini...

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“…Similar features of slow and heterogeneous dynamics were found in the CL state for different θ-M M compounds [4,7,12,13] and were ascribed to the freezing of charges on the triangular lattice. The observed two-level processes in the slow-cooled CC state with pronounced Lorentzian contributions may be attributed to electronic phase separation/phase coexistence near the first-order charge-ordering transition [34,35]. However, such processes are also observed in the CC phase even well below the metal-insulator transition.…”

Section: Dominating Two-level Processesmentioning

confidence: 90%

Comparison of the charge-crystal and charge-glass state in geometrically frustrated organic conductors studied by fluctuation spectroscopy

Thomas,

Thyzel,

Sun

et al. 2022

Preprint

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We present a systematic investigation of the low-frequency charge carrier dynamics in different charge states of the organic conductors θ-(BEDT-TTF)2M Zn(SCN)4 with M =Rb,Tl, which result from quenching or relaxing the charge degrees of freedom on a geometrically frustrated triangular lattice. Due to strong electronic correlations these materials exhibit a charge-ordering transition, which can be kinetically avoided by rapid cooling resulting in a so-called charge-glass state without long-range order. The combination of fluctuation spectroscopy and a heat pulse method allows us to study and compare the resistance fluctuations in the low-resistive quenched and the high-resistive charge-ordered state, revealing striking differences in the respective noise magnitudes. For both compounds, we find strongly enhanced resistance fluctuations right at the metal-insulator transition and a broad noise maximum in the slowly cooled charge-crystal state with partly dominating twolevel processes revealing characteristic activation energies.

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Conductivity noise across temperature-driven transitions of rare-earth nickelate heterostructures

Cited by 10 publications

References 54 publications

Resistance fluctuation spectroscopy of phase transitions in (La0.2Pr0.2Nd0.2Sm0.2Eu0.2)NiO3 thin films

Resistance fluctuation spectroscopy of phase transitions in (La0.2Pr0.2Nd0.2Sm0.2Eu0.2)NiO3 thin films

Epitaxial stabilization of ultra thin films of high entropy perovskite

Comparison of the charge-crystal and charge-glass state in geometrically frustrated organic conductors studied by fluctuation spectroscopy

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