Developing a unifying phenomenology of the high-temperature superconducting curates from NMR shift and relaxation data

Nuclear magnetic resonance—a bulk, local probe of materials’ electronic properties—has been significant for theories of high-temperature superconducting cuprates. However, more recent NMR experiments revealed several contradictions in the early interpretation of the NMR data. This cumulative thesis, comprised of six publications, aims to develop a new phenomenology based on the entirety of Cu and O NMR shift and relaxation data. The data revealed that a suppression of the Cu shifts is behind the failure of the Korringa relation, while the Cu relaxation measured with one direction of the field (c||B0) is similar for all cuprates and is Fermi-liquid like. The Cu shift and relaxation anisotropies could be explained by assuming two-spin components with different doping and temperature dependencies. A later analysis of all planar O shift and relaxation showed that a metallic-like density of states is ubiquitous to all the cuprates, irrespective of doping and material, and carries a temperature-independent but doping-dependent pseudogap, as similarly seen in the electronic entropy. This temperature-independent pseudogap is behind the suppression of the Cu shifts, but it has no influence on the Cu relaxation. Additionally, the Cu shifts measured with the field perpendicular to the c-axis reveal a family dependence. We propose a two-spin component model, explaining the family dependence in the Cu shifts, the complex Cu shift anisotropy and relaxation, and the disparity in the temperature dependence between the Cu and O shifts. This model also accounts for the missing negative shift and the long-standing Cu orbital shift discrepancy. While these conclusions are phenomenological, they must be explained by a detailed theory of the cuprate

Temperature-Independent Cuprate Pseudogap from Planar Oxygen NMR

Planar oxygen nuclear magnetic resonance (NMR) relaxation and shift data from all cuprate superconductors available in the literature are analyzed. They reveal a temperature-independent pseudogap at the Fermi surface, which increases with decreasing doping in family-specific ways, i.e., for some materials, the pseudogap is substantial at optimal doping while for others it is nearly closed at optimal doping. The states above the pseudogap, or in its absence are similar for all cuprates and doping levels, and Fermi liquid-like. If the pseudogap is assumed exponential it can be as large as about 1500 K for the most underdoped systems, relating it to the exchange coupling. The pseudogap can vary substantially throughout a material, being the cause of cuprate inhomogeneity in terms of charge and spin, so consequences for the NMR analyses are discussed. This pseudogap appears to be in agreement with the specific heat data measured for the YBaCuO family of materials, long ago. Nuclear relaxation and shift show deviations from this scenario near Tc, possibly due to other in-gap states

KONCENTRACIJA JODA U MOKRAĆI: PREDSKAZATELJ POROĐAJNE TEŽINE ILI BIOLOŠKI BILJEG ZA PROCJENU JODNOG STATUSA SAMO U ZDRAVIH TRUDNICA?

Introduction: This study determined urine iodine concentration (UIC) during gestation, assessed the maternal iodine nutrition status and correlated it with gestational age at birth (GAB) and birth weight (BW).The measurement of UIC provides the best single measurement of the iodine nutritional status in population. Objective: Determination of UIC in pregnant women in North Macedonia. Methods: This prospective study assessed the iodine nutrition status during the course of pregnancy with reference of median UIC among 364 healthy pregnant women in different gestational age (in trimester and 5-week intervals). Results: The overall and the 1st to the 3rd trimester median UIC were: 183.7, 207, 189.75 and 169.28 [μg/L], respectively. The median UIC (μg/L) results according to 5-week interval in advancing gestation were: 232.34, 200.13, 152.81, 194.39, 181.28, 160.28, 169.41 and 175.24, respectively. We detected 5.22% (19/364) and 74.72% (272/364) with the median UIC < 50 μg/L and UIC ≥ 100 μg/L, respectively. In multiple regression, the median UIC (β = 0.0000767, P = 0.929) had no statistically signifi cant prediction to the GAB. Disease prevalence results for mean UIC in detecting BW had no statistical signifi cance: area under curve (AUC) = 0.521, z-statistic (0.340), sensitivity (45.83%), specifi city (66.27%), predictive (6.59%) and P value (0.734). Conclusion: Iodine status of pregnant women in our study is generally suffi cient by World Health Organization recommendations. The median UIC in each trimester and 5-week interval has statistically insignifi cant decrease in accordance to the advancing gestation. The median UIC has no signifi cance in predicting GAB and BW.Uvod: Ova je studija utvrdila koncentraciju joda u mokraći (UIC) tijekom trudnoće, procijenila prehrambeni status joda kod majke i povezala ga s gestacijskom dobi pri rođenju (GAB) i porođajnom težinom (BW). Mjerenje UIC-a omogućava najbolje pojedinačno mjerenje prehrambenog statusa joda u populaciji. Cilj: Određivanje UIC-a trudnicama u sjevernoj Makedoniji. Metode: Ova prospektivna studija procjenjivala je prehrambeni status joda tijekom trudnoće, pozivajući se na medijan UIC 364 zdrave trudnice u različitoj gestacijskoj dobi (u intervalima tromjesečja i 5 tjedana). Rezultati: Ukupna i prosječna UIC od 1. do 3. tromjesečja bila su: 183,7, 207, 189,75 i 169,28 [μg / L]. Srednji rezultati UIC (μg / L) prema intervalu od 5 tjedana u napredovanju trudnoće bili su: 232,34, 200,13, 152,81, 194,39, 181,28, 160,28, 169,41 i 175,24. Otkrili smo 5,22 % (19/364) i 74,72 % (272/364) s medijanom UIC <50 μg / L, odnosno UIC ≥ 100 μg / L. U višestrukoj regresiji, medijan UIC (β = 0,0000767, P = 0,929) nije imao statistički značajno predviđanje za GAB. Rezultati prevalencije bolesti za srednji UIC u otkrivanju BW nisu imali statističku značajnost: područje ispod krivulje (AUC) = 0,521, z-statistika (0,340), osjetljivost (45,83 %), specifi čnost (66,27 %), prediktivna (6,59 %) i P vrijednost (0,734). Zaključak: Jodni status trudnica u našem istraživanju u pravilu je dovoljan prema preporukama Svjetske zdravstvene organizacije. Medijan UIC-a u svakom tromjesečju i intervalu od 5 tjedana statistički je beznačajno smanjen u skladu s napredovanjem trudnoće. Medijan UIC nema značenje u predviđanju GAB i BW

Developing a unifying phenomenology of the high-temperature superconducting curates from NMR shift and relaxation data

Nuclear magnetic resonance—a bulk, local probe of materials’ electronic properties—has been significant for theories of high-temperature superconducting cuprates. However, more recent NMR experiments revealed several contradictions in the early interpretation of the NMR data. This cumulative thesis, comprised of six publications, aims to develop a new phenomenology based on the entirety of Cu and O NMR shift and relaxation data. The data revealed that a suppression of the Cu shifts is behind the failure of the Korringa relation, while the Cu relaxation measured with one direction of the field (c||B0) is similar for all cuprates and is Fermi-liquid like. The Cu shift and relaxation anisotropies could be explained by assuming two-spin components with different doping and temperature dependencies. A later analysis of all planar O shift and relaxation showed that a metallic-like density of states is ubiquitous to all the cuprates, irrespective of doping and material, and carries a temperature-independent but doping-dependent pseudogap, as similarly seen in the electronic entropy. This temperature-independent pseudogap is behind the suppression of the Cu shifts, but it has no influence on the Cu relaxation. Additionally, the Cu shifts measured with the field perpendicular to the c-axis reveal a family dependence. We propose a two-spin component model, explaining the family dependence in the Cu shifts, the complex Cu shift anisotropy and relaxation, and the disparity in the temperature dependence between the Cu and O shifts. This model also accounts for the missing negative shift and the long-standing Cu orbital shift discrepancy. While these conclusions are phenomenological, they must be explained by a detailed theory of the cuprate

Developing a unifying phenomenology of the high-temperature superconducting curates from NMR shift and relaxation data

Nuclear magnetic resonance—a bulk, local probe of materials’ electronic properties—has been significant for theories of high-temperature superconducting cuprates. However, more recent NMR experiments revealed several contradictions in the early interpretation of the NMR data. This cumulative thesis, comprised of six publications, aims to develop a new phenomenology based on the entirety of Cu and O NMR shift and relaxation data. The data revealed that a suppression of the Cu shifts is behind the failure of the Korringa relation, while the Cu relaxation measured with one direction of the field (c||B0) is similar for all cuprates and is Fermi-liquid like. The Cu shift and relaxation anisotropies could be explained by assuming two-spin components with different doping and temperature dependencies. A later analysis of all planar O shift and relaxation showed that a metallic-like density of states is ubiquitous to all the cuprates, irrespective of doping and material, and carries a temperature-independent but doping-dependent pseudogap, as similarly seen in the electronic entropy. This temperature-independent pseudogap is behind the suppression of the Cu shifts, but it has no influence on the Cu relaxation. Additionally, the Cu shifts measured with the field perpendicular to the c-axis reveal a family dependence. We propose a two-spin component model, explaining the family dependence in the Cu shifts, the complex Cu shift anisotropy and relaxation, and the disparity in the temperature dependence between the Cu and O shifts. This model also accounts for the missing negative shift and the long-standing Cu orbital shift discrepancy. While these conclusions are phenomenological, they must be explained by a detailed theory of the cuprate