Interference Commensurate Oscillations in Q1D Conductors

We suggest an analytical theory to describe angular magnetic oscillations recently discovered in quasi-one-dimensional conductor (TMTSF)2PF6 [see Phys. Rev. B, 57, 7423 (1998)] and define the positions of the oscillation minima. The origin of these oscillations is related to interference effects resulting from an interplay of quasi-periodic and periodic ("commensurate") electron trajectories in an inclined magnetic field. We reproduce via calculations existing experimental data and predict some novel effects.Comment: 10 pages, 2 figure

Theory of Thermodynamic Magnetic Oscillations in Quasi-One-Dimensional Conductors

The second order correction to free energy due to the interaction between electrons is calculated for a quasi-one-dimensional conductor exposed to a magnetic field perpendicular to the chains. It is found that specific heat, magnetization and torque oscillate when the magnetic field is rotated in the plane perpendicular to the chains or when the magnitude of magnetic filed is changed. This new mechanism of thermodynamic magnetic oscillations in metals, which is not related to the presence of any closed electron orbits, is applied to explain behavior of the organic conductor (TMTSF)$_2$ClO$_4$.Comment: 11 pages + 5 figures (included

Electrotransport and magnetic properies of Cr-GaSb spintronic materials synthesized under high pressure

Electrotarnsport and magnetic properties of new phases in the system Cr-GaSb were studied. The samples were prepared by high-pressure (P=6-8 GPa) high-temperature treatment and identified by x-ray diffraction and scanning electron microscopy (SEM). One of the CrGa$_2$Sb$_2$ phases with an orthorhombic structure $Iba2$ has a combination of ferromagnetic and semiconductor properties and is potentially promising for spintronic applications. Another high-temperature phase is paramagnetic and identified as tetragonal $I4/mcm$

Sign reversals of the quantum Hall effect and helicoidal magnetic-field-induced spin-density waves in quasi-one-dimensional organic conductors

We study the effect of umklapp scattering on the magnetic-field-induced spin-density-wave phases, which are experimentally observed in the quasi-one-dimensional organic conductors of the Bechgaard salts family. Within the framework of the quantized nesting model, we show that umklapp processes may naturally explain sign reversals of the quantum Hall effect (QHE) observed in these conductors. Moreover, umklapp scattering can change the polarization of the spin-density wave (SDW) from linear (sinusoidal SDW) to circular (helicoidal SDW). The QHE vanishes in the helicoidal phases, but a magnetoelectric effect appears. These two characteristic properties may be utilized to detect the magnetic-field-induced helicoidal SDW phases experimentally.Comment: 4 pages, latex, 3 figure

Magic angle effects of the one-dimensional axis conductivity in quasi-one dimensional conductors

In quasi-one-dimensional conductors, the conductivity in both one-dimensional axis and interchain direction shows peaks when magnetic field is tilted at the magic angles in the plane perpendicular to the conducting chain. Although there are several theoretical studies to explain the magic angle effect, no satisfactory explanation, especially for the one-dimensional conductivity, has been obtained. We present a new theory of the magic angle effect in the one-dimensional conductivity by taking account of the momentum-dependence of the Fermi velocity, which should be large in the systems close to a spin density wave instability. The magic angle effect is explained in the semiclassical equations of motion, but neither the large corrugation of the Fermi surface due to long-range hoppings nor hot spots, where the relaxation time is small, on the Fermi surface are required.Comment: 4 pages, 3 figure

Acute kidney injury after primary total hip replacement

Surgical interventions that do not directly affect the urinary system can cause excretory dysfunction of kidneys. The aim. To establish the prevalence, risk factors and clinical significance of acute kidney injury after primary hip replacement performed in the clinic of the Irkutsk Scientific Centre of Surgery and Traumatology. Materials and methods. We carried out a retrospective analysis of the case histories of 109 patients who underwent primary total hip replacement under conditions of subarachnoid anesthesia in the clinic of the Irkutsk Scientific Centre of Surgery and Traumatology in 2021. Results. Postoperative changes in serum creatinine in 8 patients of the study group met the KDIGO (The Kidney Disease: Improving Global Outcomes) criteria for acute kidney injury. Initial indicators of renal excretory function in the subgroup with acute kidney injury were not different from those in the entire group. Statistically significant correlation was established between acute kidney injury and indicators of oxygen-carrying capacity of blood – initial and minimal postoperative hemoglobin concentration. Acute kidney injury in patients of the study group had a minimal effect on the clinical course of the early postoperative period. None of the patients required renal replacement therapy, re-transfer from the specialized unit to the intensive care unit or any specific treatment. The duration of postoperative stay of patients with acute kidney injury in the clinic did not increase. Conclusions. Acute kidney injury was detected in 7.3  % of patients who underwent primary total hip replacement. Risk factors for the development of postoperative acute kidney injury in  patients of the study group included relatively low initial and  minimal postoperative blood hemoglobin concentrations, which may indicate prerenal mechanism of acute kidney injury pathogenesis. Implementation of the main steps of the “renal protocol” in patients with initial glomerular filtration rate over 45 ml/min/1.73 m2 allows avoiding the development of severe clinically significant forms of postoperative acute kidney injury and complications associated with it in the early postoperative period of primary total hip replacement

Effect of umklapp scattering on the magnetic-field-induced spin-density waves in quasi-one-dimensional organic conductors

We study the effect of umklapp scattering on the magnetic-field-induced spin-density-wave (FISDW) phases which are experimentally observed in the quasi-one-dimensional organic conductors of the Bechgaard salts family. Within the framework of the quantized nesting model, we show that the transition temperature is determined by a modified Stoner criterion which includes the effect of umklapp scattering. We determine the SDW polarization (linear or circular) by analyzing the Ginzburg-Landau expansion of the free energy. We also study how umklapp processes modify the quantum Hall effect (QHE) and the spectrum of the FISDW phases. We find that umklapp scattering stabilizes phases which exhibit a sign reversal of the QHE, as experimentally observed in the Bechgaard salts. These ``negative'' phases are characterized by the simultaneous existence of two SDWs with comparable amplitudes. As the umklapp scattering strength increases, they may become helicoidal (circularly polarized SDWs). The QHE vanishes in the helicoidal phases, but a magnetoelectric effect appears. These two characteristic properties may be utilized to detect the magnetic-field-induced helicoidal SDW phases experimentally.Comment: Revtex, 27 pages, 9 figure

Interlayer Aharonov-Bohm interference in tilted magnetic fields in quasi-one-dimensional layered conductors

Different types of angular magnetoresistance oscillations in quasi-one-dimensional layered materials, such as organic conductors (TMTSF)2X, are explained in terms of Aharonov-Bohm interference in interlayer electron tunneling. A two-parameter pattern of oscillations for generic orientations of a magnetic field is visualized and compared with the experimental data. Connections with angular magnetoresistance oscillations in other layered materials are discussed.Comment: 4 pages, 4 figures. V.2: significant revision. On referee request, the second part of the paper is removed, and the first part is expande