Sign reversal of spin-polarized tunnelling magnetoresistance in 99.95% La0.7Sr0.3MnO3-0.05% Paraffin wax nanocomposite: An effect of spin-flip scattering at intergranular Paraffin wax interface

Dey, P.; Deb, D.; Debnath, Rajesh; Mandal, S. K.; Lakhani, Archana; Nath, T. K.; Roy, Jitendra Nath; Nath, A.

doi:10.1016/j.jmmm.2018.07.066

Cited by 14 publications

(9 citation statements)

References 29 publications

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“…In our earlier study on the same sample, we have observed that temperature‐dependent surface spin susceptibility (

χ_{normalb}

) changes its sign from negative to positive at the low‐temperature regime (Figure discussed previously by Dey et al). Moreover, it has already been reported that the disorder of the surface spins in nanoparticles is coupled with the core spins via exchange coupling .…”

Section: Modeling and Discussionsupporting

confidence: 72%

“…This so‐called LFMR has been found to increase with decrease in temperature in many polycrystalline CMR systems . Our 99.95% LSMO‐0.05% paraffin wax nanocomposite system has also been found to show the usual increasing behavior of LFMR with decrease in temperature from 300 to 50 K, as shown in Figure . However, LFMR is observed to decrease with decrease in temperature below 50 K, which ultimately led to sign reversal of MR and hence an overall positive MR at 10 and 5 K (Figure ).…”

Section: Description Of the Modelsupporting

confidence: 52%

“…Hence, paraffin wax acts as intergranular barrier between two neiboring LSMO grains of the composite. Furthermore, our recent report also hints toward the possible inclusions of nanometric LSMO impurities at the barrier between neiboring LSMO grains.…”

Section: Description Of the Modelmentioning

confidence: 57%

“…Furthermore, the nanosize impurity LSMO grains at the barrier also have different orientations of magnetic moments at their surface and bulk regions . We assume that most of the impurity boundary (IB) DWs attain blocked states at this low‐temperature regime . Therefore, the magnetic moments at IB domains form a larger orientation with easy axis compared with that of GB domain of the composite .…”

Section: Description Of the Modelmentioning

confidence: 99%

“…In this article, a model established by Raychaudhuri et al has been used to explain the recently reported temperature‐dependent magneto‐transport phenomenon, observed in 99.95% LSMO–0.05% paraffin wax nanocomposite sample . The model is governed by transport of electrons across GBs of the composite due to depinning of domain walls (DWs) from the GB pinning centers with the application of magnetic field.…”

Section: Introductionmentioning

confidence: 99%

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Modeling of Temperature‐Dependent Sign Reversal of Magnetoresistance in 99.95% La_0.7Sr_0.3MnO₃ − 0.05% Paraffin Wax Nanocomposite: The Role of Pinning Center at Intergrain Defect Site

Deb

Dey

2019

Physica Status Solidi (b)

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A reasonable modification of an established phenomenological model is developed to investigate the recent report on sign reversal of magnetoresistance (MR) in 99.95% La0.7Sr0.3MnO3(LSMO)−0.05% paraffin wax hybrid nanocomposite system. At zero external magnetic field (H), all the grain boundary (GB) domain walls (DWs) are assumed to remain pinned at the pinning well. Due to depinning of spin‐polarized DWs with H, a negative MR response is observed between 15 K and 300 K. The GB DWs, which are expected to be pinned with strong pinning strength at and below 10 K, have undergone spin‐flip tunneling, thereby increasing the resistance of the composite with H, i.e., positive MR. The strong pinning phenomenon associated with positive MR is analytically modeled using a skewed Gaussian distribution of pinning strength at and below 10 K.

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“…In our earlier study on the same sample, we have observed that temperature‐dependent surface spin susceptibility (

χ_{normalb}

Section: Modeling and Discussionsupporting

confidence: 72%

Section: Description Of the Modelsupporting

confidence: 52%

Section: Description Of the Modelmentioning

confidence: 57%

Section: Description Of the Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modeling of Temperature‐Dependent Sign Reversal of Magnetoresistance in 99.95% La_0.7Sr_0.3MnO₃ − 0.05% Paraffin Wax Nanocomposite: The Role of Pinning Center at Intergrain Defect Site

Deb

Dey

2019

Physica Status Solidi (b)

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Optical and Magneto‐Tunable Electrical Transport Across La_0.7Sr_0.3MnO₃, Zn_0.3Ni_0.7Fe₂O₄/CuPc Hybrid Interfaces

Deb

Nath

Pal

et al. 2023

Physica Status Solidi (a)

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In search of multifunctionality, both light and magnetic field-dependent carrier transports have been extensively studied across magnetic/organic semiconductors (OSC) interfaces. [1][2][3][4] OSC, usually comprising of elements with small atomic numbers like carbon and hydrogen, show intrinsically weak spin-orbit coupling that may lead to long spin-relaxation times making them particularly important for spintronics device applications. [1] Obstruction of spin injection at metal/insulator interface due to conductivity mismatch may be circumvented by introducing spin transport through inorganic/organic interface in spin valve devices. [2] Cinchetti et al. observed strong spin injection of around 85%-90% across Co/CuPc (copper pthalocyanine: OSC) heterojunctions and henceforth large mean free path in CuPc. [5] Spin filtering in La 0.7 Sr 0.3 MnO 3 ðLSMOÞ=Alq 3 heterojunctions is associated with SrO segregation at outermost layer of LSMO films. [6] Most recently, significant negative TMR is observed in Co=AlO x / NaDyClq/NiFe device, which surprisingly becomes positive on reversing the device structure as NiFe=AlO x /NaDyClq/Co (NaDyClq: Mononuclear quinolone molecule). This indicates change of hybrid states at spinterfaces is an important parameter for tunnel magnetoresistance (MR) tunability in ferromagnetic/ OSC heterojunctions. [7] With the help of spin injection through spin polarized hybrid states, scientists have fabricated efficient organic spin valves (OSV), which shows considerable MR response. [8][9][10][11] However, it becomes difficult to maintain large MR at room temperature (RT) due to magnetization and spin diffusion length reduction of magnetic electrodes and OSC, respectively. Therefore, researchers are also working on impedance spectroscopy of ferromagnetic/OSC devices, which gives information about carrier scattering across those spinterfaces. Barra et al. used impedance spectroscopy technique to separate carrier scattering at bulk and interface regions in LSMO=Alq 3 heterojunction devices. [12] Riminucci et al. extracted ferromagnetic/OSC interface resistance for parallel and antiparallel states in Mq3-based molecular spin valves. [13] Enhancement of photocurrent has also been observed with light illumination across magnetic/OSC interfaces owing to generation-separation process of Frankel excitons. [4] Ahmadi et al. found enhancement of photocurrent owing to photogenerated dipole-induced recombination reduction in inorganic/organic perovskite solar cells. [14] Kasem et al. observed

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Optical tunability of magnetoimpedance properties in La0.7Sr0.3MnO3-Glass nanocomposites: a signature of Opto-spintronics

Ghosh,

Deb,

Dey

2024

Appl. Phys. A

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Sign reversal of spin-polarized tunnelling magnetoresistance in 99.95% La0.7Sr0.3MnO3-0.05% Paraffin wax nanocomposite: An effect of spin-flip scattering at intergranular Paraffin wax interface

Cited by 14 publications

References 29 publications

Modeling of Temperature‐Dependent Sign Reversal of Magnetoresistance in 99.95% La_0.7Sr_0.3MnO₃ − 0.05% Paraffin Wax Nanocomposite: The Role of Pinning Center at Intergrain Defect Site

Modeling of Temperature‐Dependent Sign Reversal of Magnetoresistance in 99.95% La_0.7Sr_0.3MnO₃ − 0.05% Paraffin Wax Nanocomposite: The Role of Pinning Center at Intergrain Defect Site

Optical and Magneto‐Tunable Electrical Transport Across La_0.7Sr_0.3MnO₃, Zn_0.3Ni_0.7Fe₂O₄/CuPc Hybrid Interfaces

Optical tunability of magnetoimpedance properties in La0.7Sr0.3MnO3-Glass nanocomposites: a signature of Opto-spintronics

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Sign reversal of spin-polarized tunnelling magnetoresistance in 99.95% La0.7Sr0.3MnO3-0.05% Paraffin wax nanocomposite: An effect of spin-flip scattering at intergranular Paraffin wax interface

Cited by 14 publications

References 29 publications

Modeling of Temperature‐Dependent Sign Reversal of Magnetoresistance in 99.95% La0.7Sr0.3MnO3 − 0.05% Paraffin Wax Nanocomposite: The Role of Pinning Center at Intergrain Defect Site

Modeling of Temperature‐Dependent Sign Reversal of Magnetoresistance in 99.95% La0.7Sr0.3MnO3 − 0.05% Paraffin Wax Nanocomposite: The Role of Pinning Center at Intergrain Defect Site

Optical and Magneto‐Tunable Electrical Transport Across La0.7Sr0.3MnO3, Zn0.3Ni0.7Fe2O4/CuPc Hybrid Interfaces

Optical tunability of magnetoimpedance properties in La0.7Sr0.3MnO3-Glass nanocomposites: a signature of Opto-spintronics

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Modeling of Temperature‐Dependent Sign Reversal of Magnetoresistance in 99.95% La_0.7Sr_0.3MnO₃ − 0.05% Paraffin Wax Nanocomposite: The Role of Pinning Center at Intergrain Defect Site

Modeling of Temperature‐Dependent Sign Reversal of Magnetoresistance in 99.95% La_0.7Sr_0.3MnO₃ − 0.05% Paraffin Wax Nanocomposite: The Role of Pinning Center at Intergrain Defect Site

Optical and Magneto‐Tunable Electrical Transport Across La_0.7Sr_0.3MnO₃, Zn_0.3Ni_0.7Fe₂O₄/CuPc Hybrid Interfaces