Stretched exponential spin relaxation in organic superconductors

Gezo, J. C.; Lui, Tak Kei; Wolin, Brian; Slichter, Charles P.; Giannetta, R. W.; Schlueter, John A.

doi:10.1103/physrevb.88.140504

Cited by 12 publications

(14 citation statements)

References 61 publications

(64 reference statements)

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“…At temperatures above both phenomena vanish, indicating that they should have a common origin. The measured time dependence of the magnetization due to thermally activated flux creep follows a stretched exponential indicating the existence of a dynamic heterogeneity similar to that found in superconducting systems with magnetic phases 42,43 . The results obtained in this study suggest that defective or strained regions trigger both phenomena in the diamond lattice, a lattice composed of only light elements, C and N, this last with a relatively small concentration.…”

Section: Introductionsupporting

confidence: 64%

Unconventional Magnetization below 25 K in Nitrogen-doped Diamond provides hints for the existence of Superconductivity and Superparamagnetism

Barzola‐Quiquia

Stiller

Esquinazi³

et al. 2019

Sci Rep

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The magnetization of nitrogen-doped single crystalline diamond bulk samples shows unconventional field and temperature hysteresis loops at T 25 K. The results suggest the existence of superparamagnetic and superconducting regions in samples with nitrogen concentration <200 ppm. Both phases vanish at temperatures above 25 K where the samples show diamagnetic behavior similar to undoped diamond. The observation of superparamagnetism and superconductivity is attributed to the nitrogen doping and to the existence of defective regions. From particle-induced X-ray emission with ppm resolution we rule out that the main observations below 25 K are due to magnetic impurities. We investigated also the magnetic properties of ferromagnetic/high-temperature superconducting oxide bilayers. The magnetization results obtained from those bilayers show remarkable similarities to the ones in nitrogen-doped diamond.

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Section: Introductionsupporting

confidence: 64%

Unconventional Magnetization below 25 K in Nitrogen-doped Diamond provides hints for the existence of Superconductivity and Superparamagnetism

Barzola‐Quiquia

Stiller

Esquinazi³

et al. 2019

Sci Rep

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show abstract

Section: Resultsmentioning

confidence: 99%

“…By contrast, the I ds value with 2D perovskite dielectric first increases and then gradually saturates. Here, we modify the above-mentioned stretched exponential function to describe the I ds decay caused by the perovskite layer polarization associated to ionic migration 29 , 30 : where β refers to the dispersion parameter, and τ p represents the characteristic time constant for ionic migration. Here, charge trapping and ionic migration are independent phenomena.…”

Section: Resultsmentioning

confidence: 99%

Rational design of Al2O3/2D perovskite heterostructure dielectric for high performance MoS2 phototransistors

Jiang

Zou

et al. 2020

Nat Commun

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Two-dimensional (2D) Ruddlesden-Popper perovskites are currently drawing significant attention as highly-stable photoactive materials for optoelectronic applications. However, the insulating nature of organic ammonium layers in 2D perovskites results in poor charge transport and limited performance. Here, we demonstrate that Al 2 O 3 /2D perovskite heterostructure can be utilized as photoactive dielectric for high-performance MoS 2 phototransistors. The type-II band alignment in 2D perovskites facilitates effective spatial separation of photo-generated carriers, thus achieving ultrahigh photoresponsivity of >10 8 A/ W at 457 nm and >10 6 A/W at 1064 nm. Meanwhile, the hysteresis loops induced by ionic migration in perovskite and charge trapping in Al 2 O 3 can neutralize with each other, leading to low-voltage phototransistors with negligible hysteresis and improved bias stress stability. More importantly, the recombination of photo-generated carriers in 2D perovskites depends on the external biasing field. With an appropriate gate bias, the devices exhibit wavelengthdependent constant photoresponsivity of 10 3-10 8 A/W regardless of incident light intensity.

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“…Stretched exponential relaxation can be the result of heterogenous dynamics, reflecting a superposition of different correlation functions for the proton motions 19 21 32 . Upon increasing n , a random distribution of correlation functions increase, leading to an inhomogeneous system 18 32 . The stretched exponential behavior for each resonance line was only shown in the present sample, unlike in previous sample synthesized at the temperature as low as 573 K, in which double-exponential type of spin-lattice relaxation was observed 17 .…”

Section: Resultsmentioning

confidence: 99%

“…NMR relaxometry is a powerful technique of atomic-scale access to probe ion hopping motion in solids 18 19 20 . The laboratory-frame relaxation rate is effective for probing nuclear spin precessing in radio frequency range, i.e., fast diffusing spins.…”

mentioning

confidence: 99%

NMR Observation of Mobile Protons in Proton-Implanted ZnO Nanorods

Park

Kwon

Lee

2016

Sci Rep

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The diffusion properties of H+ in ZnO nanorods are investigated before and after 20 MeV proton beam irradiation by using 1H nuclear magnetic resonance (NMR) spectroscopy. Herein, we unambiguously observe that the implanted protons occupy thermally unstable site of ZnO, giving rise to a narrow NMR line at 4.1 ppm. The activation barrier of the implanted protons was found to be 0.46 eV by means of the rotating-frame spin-lattice relaxation measurements, apparently being interstitial hydrogens. High-energy beam irradiation also leads to correlated jump diffusion of the surface hydroxyl group of multiple lines at ~1 ppm, implying the presence of structural disorder at the ZnO surface.

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Stretched exponential spin relaxation in organic superconductors

Cited by 12 publications

References 61 publications

Unconventional Magnetization below 25 K in Nitrogen-doped Diamond provides hints for the existence of Superconductivity and Superparamagnetism

Unconventional Magnetization below 25 K in Nitrogen-doped Diamond provides hints for the existence of Superconductivity and Superparamagnetism

Rational design of Al2O3/2D perovskite heterostructure dielectric for high performance MoS2 phototransistors

NMR Observation of Mobile Protons in Proton-Implanted ZnO Nanorods

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