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Multi-orbital physics in quasi-two-dimensional electron gases (q2DEGs) triggers intriguing phenomena not observed in bulk materials, such as unconventional superconductivity and magnetism. Here, we investigate the mechanism of orbital selective switching of the spin-polarization in the oxide q2DEG formed at the (001) interface between the LaAlO3, EuTiO3 and SrTiO3 band insulators. By using density functional theory calculations, transport, magnetic and x-ray spectroscopy measurements, we find that the filling of titanium-bands with 3dxz/3dyz orbital character in the EuTiO3 layer and at the interface with SrTiO3 induces an antiferromagnetic to ferromagnetic switching of the exchange interaction between Eu-4f7 magnetic moments. The results explain the observation of the carrier density-dependent ferromagnetic correlations and anomalous Hall effect in this q2DEG, and demonstrate how combined theoretical and experimental approaches can lead to a deeper understanding of emerging electronic phases and serve as a guide for the materials design of advanced electronic applications. [ABSTRACT FROM AUTHOR]

The new frontier for spintronics is the realization of devices in which the spin can be controlled by electric fields. Multiferroics, materials exhibiting strong interplay between spin and orbital degrees of freedom, are candidates for the realization of such a paradigm. In this work, we study the magnetoelectric coupling in epitaxial BiMnO 3 thin films which exhibit a large saturation magnetization. By combining X-ray absorption spectroscopy data and theoretical modeling, we demonstrate that BiMnO 3 thin films have an improper magnetoelectric behavior, characterized by competing antiferromagnetic and ferromagnetic correlations. As a consequence, we show that in these materials the Mn-3d orbital and magnetic orders can be tuned via the ferroelectric polarization, opening perspectives for the realization of novel spintronic devices. [ABSTRACT FROM AUTHOR]

High-temperature copper oxide superconductors consist of stacked CuO2 planes, with electronic band structures and magnetic excitations that are primarily two-dimensional1,2, but with superconducting coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state3,4 within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides5-7 reveals their charge origin, that is, without mixing with magnetic components5-7. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO2 planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought ‘acoustic plasmon’, which is a branch of distinct charge collective modes predicted for layered systems8-12 and argued to play a substantial part in mediating high-temperature superconductivity10-12. Resonant inelastic X-ray scattering on electron-doped copper oxide superconductors reveals a three-dimensional charge collective mode, which has properties suggestive of the long-sought acoustic plasmon. [ABSTRACT FROM AUTHOR]

The electron-phonon interaction is a major factor influencing the competition between collective instabilities in correlated-electron materials, but its role in driving high-temperature superconductivity in the cuprates remains poorly understood. We have used high-resolution inelastic X-ray scattering to monitor low-energy phonons in YBa2Cu3O6.6 (superconducting transition temperature Tc = 61 K), which is close to a charge-density-wave (CDW) instability. Phonons in a narrow range of momentum space around the CDW ordering vector exhibit extremely large superconductivity-induced line-shape renormalizations. These results imply that the electron-phonon interaction has sufficient strength to generate various anomalies in electronic spectra, but does not contribute significantly to Cooper pairing. In addition, a quasi-elastic 'central peak' due to CDW nanodomains is observed in a wide temperature range above and below Tc, suggesting that the gradual onset of a spatially inhomogeneous CDW domain state with decreasing temperature is a generic feature of the underdoped cuprates. [ABSTRACT FROM AUTHOR]

One of the most intensely studied scenarios of high-temperature superconductivity (HTS) postulates pairing by exchange of magnetic excitations. Indeed, such excitations have been observed up to optimal doping in the cuprates. In the heavily overdoped regime, neutron scattering measurements indicate that magnetic excitations have effectively disappeared, and this has been argued to cause the demise of HTS with overdoping. Here we use resonant inelastic X-ray scattering, which is sensitive to complementary parts of reciprocal space, to measure the evolution of the magnetic excitations in La2−xSrxCuO4 across the entire phase diagram, from a strongly correlated insulator (x = 0) to a non-superconducting metal (x = 0.40). For x = 0, well-defined magnon excitations are observed. These magnons broaden with doping, but they persist with a similar dispersion and comparable intensity all the way to the non-superconducting, heavily overdoped metallic phase. The destruction of HTS with overdoping is therefore caused neither by the general disappearance nor by the overall softening of magnetic excitations. Other factors, such as the redistribution of spectral weight, must be considered. [ABSTRACT FROM AUTHOR]

In the search for the mechanism of high-temperature superconductivity, intense research has been focused on the evolution of the spin excitation spectrum on doping from the antiferromagnetic insulating to the superconducting state of the cuprates. Because of technical limitations, the experimental investigation of doped cuprates has been largely focused on low-energy excitations in a small range of momentum space. Here we use resonant inelastic X-ray scattering to show that a large family of superconductors, encompassing underdoped YBa2Cu4O8 and overdoped YBa2Cu3O7, exhibits damped spin excitations (paramagnons) with dispersions and spectral weights closely similar to those of magnons in undoped cuprates. The comprehensive experimental description of this surprisingly simple spectrum enables quantitative tests of magnetic Cooper pairing models. A numerical solution of the Eliashberg equations for the magnetic spectrum of YBa2Cu3O7 reproduces its superconducting transition temperature within a factor of two, a level of agreement comparable to that of Eliashberg theories of conventional superconductors. [ABSTRACT FROM AUTHOR]

X-ray absorption spectroscopy in the presence of an electric field has been used to study the doping mechanism of the CuO2 planes in Nd1+xBa2-xCu3O7 compounds. The electric field effect doping is well-known as a method to modify the electrical properties of a thin film using an external gate voltage and in the copper based high critical temperature superconductors (HTS), it has been used to shift the critical temperature and even to induce phase transitions. Field effect experiments in ultra-thin HTS are usually interpreted by supposing that the induced charges develop into carriers in the CuO2 conducting planes, thus changing the filling of the Zhang-Rice (ZR) band. Here we show that the polarization charges in both insulating and superconducting films, are mainly confined in the charge reservoir, and in particular in the CuO chains. The characteristics of the charge reservoir layer determine the doping of the CuO2 planes, achieved by transfer of a fraction of the total injected charges. Moreover we found that holes injection in the CuO2 planes is reduced in oxygen deficient NdBCO films. [ABSTRACT FROM AUTHOR]

A theoretical description of the Fano-effect in the angle-integrated valence-band photoemission (VB XPS) of paramagnetic solids is presented that is based on the one-step model of photoemission and relativistic multiple scattering theory. Applications to fcc-Cu and fcc-Ag led to a very satisfying agreement with recent experimental data that show the Fano-effect, i.e., a finite spin polarisation of the photoelectrons is found for excitation with circularly polarised radiation. As can be demonstrated by model calculations, this finding is caused by the presence of spin–orbit coupling. To allow for a more detailed discussion of the spectra, a simplified description of the Fano-effect is presented that treats spin–orbit coupling as a perturbation. [ABSTRACT FROM AUTHOR]

We discuss the application of resonant inelastic X-ray scattering to the study of magnetic systems in the soft X-ray range. To this end we distinguish two broad areas. In the first the layout of the experiment is such that the absorption magnetic circular dichroism (MCD) is not zero. In the second the magnetisation is perpendicular to the incident helical beam so that the absorption MCD is zero. In the first area we summarise published results on Fe-Co alloys and we present new data on Mn impurities in Ni together with calculations. In the second area we summarise published results on Ni in Ni-ferrite with final 3s shell excitation and we present new results on Co-metal and Co in Co-ferrite measured with a new approach. This is based on the incident energy dependence of the integral of the Raman spectrum in inner shell excitation (integrated resonant Raman scattering). The potentialities and the limitations of the above methods are critically presented. [ABSTRACT FROM AUTHOR]

The bone mineral density (BMD) at the lumbar spine, proximal femur, and total skeleton was evaluated in 38 men with primary osteoporosis and vertebral fractures. BMD of the patients was significantly reduced over all skeletal areas compared with controls. The Z-score of the lumbar spine (-2.8 +/- 0.9) was less than that of the other areas (P < 0.001) except the legs (-2.5 +/- 1.1) (p.n.s.) showing that bone loss had a tendency to be greater over the axial skeleton. Vertebral dimensions compared with age-matched controls were as follows: projected L2-L4 area (cm 2): 45.7 +/- 5.6 versus 53.7 +/- 3. 6 (P < 0.001); vertebral width (cm): 4.37 +/- 0.44 versus 4.90 +/- 0. 36 (P < 0.001). Serum biochemical parameters and testosterone levels were similar between osteoporotic and control men. We conclude that men with vertebral osteoporotic fractures have reduced vertebral BMD and vertebral dimensions compared with age-matched controls. Thus, these findings indicate that the achievement of a reduced bone size at the end of the growth period or a failure of periosteal increase during adult life is likely to contribute to the pathogenesis of the vertebral fractures observed in older men. [ABSTRACT FROM AUTHOR]

The bone mineral density (BMD) of the radius and spine was determined by photo absorptiometry in a large number of controls (radius: n = 111; spine: n = 85; age range: 50-79 years) and osteoporotic women (radius: n = 98; spine n = 140; age range: 50-79 years) with at least one "atraumatic" vertebral compression fracture. Compared to age-matched controls, the BMD of the osteoporotic women showed the following diminutions: sixth decade: radius: -9.1%; spine: -25%; femur: -33%; seventh decade: radius: -16%; spine: -19%; femur: -23%; eighth decade: radius: -21%; spine: -20%; femur: -24%. The BMD was significantly diminished at all sites in all decades but in contrast to the radius, the difference from controls was bigger in the spine and femur in the sixth decade than in the seventh and eighth decade. In the osteoporotic women there was a significant correlation between radius BMD and age (r = -0.56; P less than 0.01) but not between spine or femoral BMD and age. The femoral neck BMD was also determined in a subset group of female controls (n = 68), patients with crush fractures of the spine without a fracture of the hip (n = 46), and in patients with fractures of the proximal femur (n = 21). There was no difference among these groups in mean age (64 +/- 7, range: 50-79 years). Patients with hip fracture and spine fracture showed bone diminution in all three regions that was significantly below controls (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS) [ABSTRACT FROM AUTHOR]

Twenty-one women with primary osteoporosis received an intramuscular injection of 100 IU of salmon calcitonin at 8 AM. Blood samples IU of salmon calcitonin at 8 AM. Blood samples were collected up to 5 h postcalcitonin and urine was collected for 24 h in three periods of 8 h each. A significant fall of the total hydroxyproline excretion (THP) was observed in every period but the maximum effect took place 8-16 h postcalcitonin. The effect was more pronounced in those patients with a greater basal excretion of THP and in those with a more significant diminution of their bone mass. A significant diminution of the urinary excretion of calcium was found 8-24 h postcalcitonin, while phosphate excretion increased throughout the three 8 h periods. The effect of calcitonin in osteoporotic women was compared with the results obtained in 9 patients with Paget's disease. In absolute in 9 patients with Paget's disease. In absolute values the fall of THP excretion was significantly greater in the pagetic patients but the percentage diminution was not significantly different in osteoporotic women and in pagetic patients. Salmon calcitonin induced a significant acute diminution of bone turnover in patients with osteoporosis, as defined by decreases in total urinary hydroxyproline. The calcitonin-induced hypocalcemia does not seem to be an accurate index of the hormone action in osteoporosis. [ABSTRACT FROM AUTHOR]

We present results on resonant inner-shell scattering in Gd across the M threshold; the scattering channel with formally a 4p hole in the final state is studied. Two scattering channels are in competition: one at constant transferred energy and another at constant outgoing energy. The branching ratio of the process at constant transferred energy is about 5%. We isolate the many-body satellite structure of the formally 4 final hole state and we discuss the importance of the multiplet splitting and of the super Coster-Kronig conversion of this state into another final state with two 4d holes. The results with resonant M excitation are also compared with those of non-resonant excitation well above the M threshold. Guidelines for future research are briefly presented. [ABSTRACT FROM AUTHOR]

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On 7 patients with mild-to-moderately active Paget's disease, 200 IU of salmon calcitonin (SCT) nasal spray (NS), induced a significant decrease of the total urinary hydroxyproline excretion (THP) during the 8-16 hour and the 0-24 hour (P less than 0.05) periods after treatment as compared to control day. However, the administration of 100 IU of SCT intramuscularly (i.m.) caused a significantly greater effect than 200 IU-NS during the second 8 hour period after its administration (P less than 0.01) and on the over-all 24 hour effect (P less than 0.05). On 3 patients with severe Paget's disease, SCT-NS was essentially ineffective whereas the injection of SCT induced a marked diminution of the THP excretion. [ABSTRACT FROM AUTHOR]