Magnetism and Superconductivity in Iron-based by Franziska Hammerath

By Franziska Hammerath

Nuclear Magnetic Resonance (NMR) has been a primary participant within the experiences of superconducting fabrics for lots of a long time. This neighborhood probe method permits the research of the static digital homes in addition to of the low power excitations of the electrons within the basic and the superconducting kingdom. On that account it has additionally been greatly utilized to Fe-based superconductors from the very starting in their discovery in February 2008. This dissertation includes a few of these first actual NMR effects, reflecting the novel nature of superconductivity and its powerful hyperlink to magnetism within the investigated compounds LaO1–xFxFeAs and LiFeAs.

Show description

Read Online or Download Magnetism and Superconductivity in Iron-based Superconductors as Probed by Nuclear Magnetic Resonance PDF

Best solid-state physics books

Fractal concepts in condensed matter physics

Concisely and obviously written through most advantageous scientists, this e-book presents a self-contained creation to the fundamental ideas of fractals and demonstrates their use in a variety of themes. The authors’ unified description of other dynamic difficulties makes the publication super available.

Defects at Oxide Surfaces

This booklet offers the fundamentals and characterization of defects at oxide surfaces. It offers a state of the art assessment of the sector, containing details to some of the sorts of floor defects, describes analytical the right way to learn defects, their chemical job and the catalytic reactivity of oxides.

Mesoscopic Theories of Heat Transport in Nanosystems

This ebook provides generalized heat-conduction legislation which, from a mesoscopic point of view, are suitable to new purposes (especially in nanoscale warmth move, nanoscale thermoelectric phenomena, and in diffusive-to-ballistic regime) and even as stay alongside of the speed of present microscopic examine.

Introduction to magnetic random-access memory

Magnetic random-access reminiscence (MRAM) is poised to exchange conventional machine reminiscence in keeping with complementary metal-oxide semiconductors (CMOS). MRAM will surpass all different different types of reminiscence units when it comes to nonvolatility, low strength dissipation, speedy switching velocity, radiation hardness, and sturdiness.

Extra info for Magnetism and Superconductivity in Iron-based Superconductors as Probed by Nuclear Magnetic Resonance

Example text

52kB Tc . 2 Spin-Lattice Relaxation Rate 39 Another famous example is superconducting A3 C60 (A = alkali metal). For this class of superconductors the Hebel-Slichter peak is suppressed by the application of high magnetic fields, suggesting an intermediate coupling regime within the BCS theory [96]. Other possible effects which could lead to a suppression of the Hebel-Slichter peak are a spread in superconducting transition temperatures within a sample or slight gap anisotropies [96]. While the existence of a Hebel-Slichter peak points strongly towards a conventional BCS s-wave pairing mechanism, the absence of it is not sufficient to interpret spin-lattice relaxation rates correctly in terms of other gap symmetries.

B|2 is the transition matrix element containing the coupling of the nuclear spins to the electronic system (hyperfine coupling). Experimentally, one can only measure the net transition rate between the energy levels E = E + ω and E, which is given by the difference of the transition rate from E to E , αs,E→E and the one back from E to E, αs,E →E : αs,E↔E = αs,E→E − αs,E →E ∝ NBCS (E)f (E)NBCS (E )[1 − f (E )] − NBCS (E )f (E )NBCS (E)[1 − f (E)] = NBCS (E)NBCS (E )[f (E) − f (E )] . 15) Furthermore, only processes with an energy difference E − E = ω are interesting.

C) Calculated Fermi-surface topology of LaOFeAs based on an effective four-band model. The Fermi surface consists of two hole pockets around Γ = (0, 0) and two electron pockets around M = (π, π) in the folded Brillouin zone. Blue (green) arrows denote main scattering vectors with Qafm = (π, π) (interband) and with the incommensurate intraband scattering QSDW .

Download PDF sample

Rated 4.56 of 5 – based on 46 votes