Related papers: Nonlinear Magnetization in Superconductors with s+…
The O(N) model of layered antiferro- and ferromagnets with a weak interlayer coupling and/or easy-axis anisotropy is considered. A renormalization group (RG) analysis in this model is performed, the results for N=3 being expected to agree…
YBa$_2$Cu$_3$O$_7$ (YBCO) exhibits a large anisotropy between the $a$ and $b$ axes in the CuO$_2$ planes because of the presence of CuO chains. In order to account for such an anisotropy we develop a Ginzburg-Landau (GL) theory for an…
We show that the field dependence of the magnetic penetration depth ($\lambda$), for which muon spin rotation ($\mu$SR) is an excellent microscopic probe, provides useful information on the degree of anisotropy for the superconducting order…
It is a highly nontrivial question whether a magnetization can be induced by applying a nonlinear temperature gradient in the absence of any linear component. In this work, we address this issue and provide explicit examples demonstrating…
The superconductor Nb$_3$Sn has a high critical temperature and high critical field, widely used for high-field superconducting magnets. In this work we investigate its microscopic electronic structure with $^{93}$Nb nuclear magnetic…
We consider an unconventional superconductor in a low frequency harmonic magnetic field. In the Meissner regime at low T a nonlinear magnetic response arises from quasiparticle excitations near minima in the energy gap. Various physical…
A simplified model of anisotropic magnetic susceptibility in the Meissner-London vortex-free state of cuboidal superconducting samples is presented. Using this model, precision measurements of the magnetic response in three perpendicular…
It was recently shown that conventional phonon-electron interactions induce triplet pairing states in time-reversal invariant 3D Dirac semi - metals provided magnetic impurities or exchange interactions are strong enough?. The order…
A Ginzburg-Landau theory is developed for unconventional superconductors with the three relevant singlet pairing channels. Various consequences of the sub-dominant channels (i.e., s- and d_{xy}-channels) are examined in detail. (1) In the…
We study the three-dimensional Ginzburg-Landau model of superconductivity for strong applied magnetic fields varying between the second and third critical fields. In this regime, it is known from physics that superconductivity should be…
I present a Ginzburg-Landau theory for hexagonal oscillations of the upper critical field of UPt$_3$ near $T_c$. The model is based on a $2D$ representation for the superconducting order parameter, $\vec{\eta}=(\eta_1,\eta_2)$, coupled to…
Single crystals of the oxypnictide superconductors SmFeAsO_(0.8)F_(0.2) and NdFeAsO_(0.8)F_(0.2) with T_c in the range of 44 K to 48 K were investigated by torque magnetometry. An analysis of the data in terms of a recently proposed model…
Here, by applying a comprehensive approach including magnetic, transport measurements, ARPES band structure measurements, DFT calculations, and analytical theory consideration, we unveil the puzzling origin of the negative isotropic…
We extend to magnetically ordered phases a recently developed expansion in 1/d for coupled-dimer Heisenberg magnets, where d is the number of space dimensions. This extension utilizes generalized bond operators describing spin excitations…
We study the two dimensional quantum Heisenberg antiferromagnet on the square lattice with easy-axis exchange anisotropy. By the semiclassical method called pure-quantum self-consistent harmonic approximation we analyse several…
We investigated the nonlinear Meissner effect (NLME) in Nb$_3$Sn thin film coplanar resonators by measuring the resonance frequency as a function of a parallel magnetic field at different temperatures. We used low rf power probing in films…
We present a theoretical description of the London penetration depth of a multi-band superconductor in the case when both superconducting and spin-density wave orders coexist. We focus on clean systems and zero temperature to emphasize the…
A simple procedure to extract anisotropic London penetration depth components from the magnetic susceptibility measurements in realistic samples of cuboidal shape is described.
We investigate the magnetization process for a quasi-one-dimensional S=1 antiferromagnet with bond alternation. By combining the density matrix renormalization group method with the interchain mean-field theory, we discuss how the…
The recently discovered intermetallic superconductor MgB2 appears to have a highly anisotopic upper critical field with Hc2(max)/Hc2(min} = \gamma > 5. In order to determine the temperature dependence of both Hc2(max) and Hc2(min) we…