Spin-glass and variable range hopping quantum interference magnetoresistance in FeSr2Y1.3Ce0.7Cu2O10−x

Sambale, Sebastian; Williams, G. V. M.; Stephen, Jibu; Chong, Shen V.

doi:10.1088/2053-1591/1/4/046112

Cited by 4 publications

(4 citation statements)

References 31 publications

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“…The hole concentration in the OR sample is consistent with a non-superconducting and insulating sample where the Cu moments in the CuO 2 plane order antiferromagnetically. The ZFC and FC magnetization data from the OS samples (not shown) are similar to the magnetization shown in figure 8.2 (Sambale et al [13]) where there is a peak in the ZFC moment at ∼22 K that arises from a spin-glass [13]. It can be seen in figure 8.14 that the peak occurs at approximately the same temperature in the OR sample and hence it is apparent that the spin-glass temperature is not affected by a large reduction in the oxygen content.…”

Section: The Effect Of Oxygen Loadingsupporting

confidence: 74%

“…1000) 50 (10) Table 5.18: CW fit parameters for the linewidth. (20) 450(30) 0.07 ab B 35 (10) 9000(3000) 0.13 c B 180 (20) 580(60) 0.13 ab B 22 (13) The fits for c B 0 are good over the whole fitting region, so it seems appropriate to say that 2D spin fluctuations are the major relaxation mechanism. The 2D spin fluctuation behavior is supported by the anisotropy ratio, which is shown in figure 5.41.…”

Section: Nmr Linewidthmentioning

confidence: 99%

“…The presence of both magnetic as well as superconducting ordering makes these compounds the ideal candidates to study the competing electronic and magnetic interactions. Furthermore, they display a wide variety of interesting physical properties, such as a low temperature spin glass transition and a high negative magnetoresistance in FeSr 2 Y 2-x Ce x Cu 2 O 10-y (Fe1222) [13] and a superconducting transition temperature depending on the Fe distribution in FeSr 2 YCu 2 O 6+y (Fe1212) [14].…”

Section: Introductionmentioning

confidence: 99%

“…13: T 1 for CeFeAsO 0.80 F 0.20 at different temperatures and both field orientations with their uncertainties (in brackets).…”

mentioning

confidence: 99%

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Magnetic and electronic properties of iron-based superconducting systems

Sambale¹

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This thesis is motivated by the large variety of high-temperature superconductors that contain iron in the superconducting layer. This number has grown rapidly since the discovery in 2008 of the iron-pnictides (and chalcogenides), where iron and arsenic form the superconducting layer. Also of interest are the iron-cuprate hybrid materials, where one out of three copper atoms is replaced by iron. The aim is to understand the superconducting, magnetic and electronic properties of these materials in respect to their iron content. This thesis describes some of these properties for the iron-pnictide compounds of CeFeAsO₁₋xFx and AFe₂As₂ (A=Ba, Sr), and for the ironcuprate hybrids of FeSr₂YCu₂O₆₊y and FeSr₂Y₂₋xCexCu₂O₁₀₋y. Here it has been found that CeFeAsO₁₋xFx follows a 3D fluctuation conductivity above the superconducting transition and the thermal activation energy is correlated to the critical current density within a two fluid-flux creep model below the superconducting transition. NMR measurements show that there is considerable charge disorder within the superconducting doping region. The AFe₂As₂ show a positive magnetoresistance, which could be interpreted through three-carrier transport. Superconducting samples of SrFe₂As₂ display a large enhancement in the magnetoresistance below the superconducting transition up to 1600 %, which is due to three-carrier transport through metallic and superconducting regions in an inhomogeneous state. The superconducting properties of the iron-cuprate FeSr₂YCu₂O₆₊y in respect to the location of iron was studied under the influence of electron and hole doping and with additional magnetic impurities. FeSr₂Y₂₋xCexCu₂O₁₀₋y shows a disorder induced spin-glass state and strong localization depending on the doping.

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Section: The Effect Of Oxygen Loadingsupporting

confidence: 74%

Section: Nmr Linewidthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…13: T 1 for CeFeAsO 0.80 F 0.20 at different temperatures and both field orientations with their uncertainties (in brackets).…”

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confidence: 99%

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Magnetic and electronic properties of iron-based superconducting systems

Sambale¹

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The effect of oxygen content on the magnetic and transport properties of FeSr2Y1.5Ce0.5Cu2O8+x

Sambale

Williams

Chong

2016

Physica B: Condensed Matter

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Mott type variable range hopping conduction and magnetoresistance in p-type CuIn3Te5 semiconductor compound

Essaleh

Wasim

Marín

et al. 2017

Journal of Applied Physics

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Variable range hopping (VRH) conduction of Mott type for a constant and non-vanishing density of states at the Fermi level is observed over a wide range of temperature between 45 and 210 K in the ordered defect compound CuIn3Te5 (CIT135). For this type of electrical conduction at a very high temperature, not reported before in elemental, II-VI, and I-III-VI2 compound semiconductors, we employed three different methods to analyze the data and to confirm this behavior. The occurrence of VRH at very high temperatures is explained as due to the presence of the electrically inactive (InCu+2 + 2 VCu−1) donor-acceptor defect pairs in CIT135. This defect-pair partially annihilates the shallow acceptor defect state Cu vacancy, which is responsible for the activated electrical conductivity observed in p-type ternary I-III-VI2 chalcopyrite compounds in the temperature range of liquid nitrogen. In such conditions, the only acceptor level available for electrical conduction in CIT135 is a deep acceptor state whose activation energy is about 200 meV and cannot be activated below about 200 K. Hence, the VRH conduction mechanism dominates the electrical properties of this material up to about 200 K. The study of the temperature and magnetic field dependence of the magnetoresistance (MR) up to 27 T is made by taking into consideration different theoretical models. To explain the negative MR at lower fields, the theory based on quantum interference is used. At higher magnetic fields, the MR becomes positive and is explained with the model based on the shrinkage of the wave function.

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Spin-glass and variable range hopping quantum interference magnetoresistance in FeSr₂Y_1.3Ce_0.7Cu₂O_10−x

Cited by 4 publications

References 31 publications

Magnetic and electronic properties of iron-based superconducting systems

Magnetic and electronic properties of iron-based superconducting systems

The effect of oxygen content on the magnetic and transport properties of FeSr2Y1.5Ce0.5Cu2O8+x

Mott type variable range hopping conduction and magnetoresistance in p-type CuIn3Te5 semiconductor compound

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