Related papers: Measuring the Penetration Depth Anisotropy in MgB$…
The anisotropy of MgB2 is still under debate: its value, strongly dependent on the sample and on the measuring method, ranges between 1.2 and 13. In this work we present our results on a MgB2 c-oriented superconducting thin film. To…
Single crystals of MgB2 with a size up to 1.5x0.9x0.2 mm3 have been grown with a high pressure cubic anvil technique. The crystal growth process is very peculiar and involves an intermediate nitride, namely MgNB9. Single crystals of BN and…
Micromagnetic small-angle neutron scattering theory is well established for analyzing spin-misalignment scattering data of bulk ferromagnets. Here, this theory is extended to allow for a global uniaxial magnetic anisotropy (texture) of the…
The flux line lattice in CaAlSi has been studied by small angle neutron scattering. A well defined hexagonal flux line lattice is seen just above Hc1 in an applied field of only 54 Oe. A 30 degree reorientation of this vortex lattice has…
The vortex lattice (VL) in the high-kappa superconductor YBa2Cu3O7, at 2 K and with the magnetic field parallel to the crystal c-axis, undergoes a sequence of transitions between different structures as a function of applied magnetic field.…
The results of first principles calculations of the electronic structure and the electron-phonon interaction in MgB2 are used to study theoretically the temperature dependence and anisotropy of the magnetic field penetration depth. The…
We present a comprehensive study of magnon excitations in the tetragonal easy-plane anti-ferromagnet Bi$_2$CuO$_4$ using inelastic neutron scattering and spin wave analyses. The nature of low energy magnons, and hence the anisotropy in this…
We have measured the magnetic penetration depth of the recently discovered binary superconductor MgB_2 using muon spin rotation and low field $ac$-susceptibility. From the damping of the muon precession signal we find the penetration depth…
The magnetic penetration depth anisotropy $\gamma_\lambda=\lambda_{c}/\lambda_{ab}$ ($\lambda_{ab}$ and $\lambda_{c}$ are the in-plane and the out-of-plane components of the magnetic penetration depth) in a CaKFe$_4$As$_4$ single crystal…
We have observed a magnetic vortex lattice (VL) in BaFe2(As_{0.67}P_{0.33})2 (BFAP) single crystals by small-angle neutron scattering (SANS). With the field along the c-axis, a nearly isotropic hexagonal VL was formed in the field range…
Based on a detailed modeling of the Fermi surface topology of MgB2 we calculated the anisotropy of the upper critical field Bc2 within the two gap model. The sigma-band is modeled as a distorted cylinder and the pi-band as a half-torus,…
The superconducting and magnetic properties of HoNi2B2C single crystals are investigated through transport, magnetometry and small-angle neutron scattering measurements. In the magnetic phases that enter below the superconducting critical…
Anisotropic penetration of magnetic flux in MgB2 films grown on vicinal sapphire substrates is investigated using magneto-optical imaging. Regular penetration above 10 K proceeds more easily along the substrate surface steps, anisotropy of…
The magnetic penetration depth, $\lambda^{-2}(T)$, in the basal plane of a magnesium diboride (MgB$_2$) film was measured using a two-coil mutual inductance technique at 50 kHz. This film has $T_c\simeq 38$ K, $\Delta T_c \leq 1$ K, and…
We examine the interplay between anisotropy of the in-plane magnetization and the nodal gap structure on the basis of the approximate analytic solution in the quasiclassical formalism. We show that a four-fold oscillation appears in the…
The temperature dependence of the London penetration depth ($\lambda$) and coherence length ($\xi$) has been deduced from Hall probe magnetization measurements in high quality MgB$_2$ single crystals in the two main crystallographic…
We employ magnetic small-angle neutron scattering to investigate the magnetic interactions in $(Fe_{0.7}Ni_{0.3})_{86}B_{14}$ alloy, a HiB-NANOPERM-type soft magnetic nanocrystalline material, which exhibits an ultrafine microstructure with…
Here we report the growth of sub-millimeter MgB2 single crystals of various shapes under high pressure in Mg-B-N system. Structure refinement using a single-crystal X-ray diffraction analysis gives lattice parameters a=3.0851(5) A and…
We have observed marked transport anisotropy in short period (a=92 nm) unidirectional lateral superlattices around filling factors nu=5/2 and 7/2: magnetoresistance shows a sharp peak for current along the modulation grating while a dip…
Data on macroscopic superconducting anisotropy of MgB$_2$ are reviewed. The data are described within a weak coupling two-gaps anisotropic s-wave model of superconductivity. The calculated ratio of the upper critical fields…