Matthew Lawson

Coexistence of cluster spin glass and superconductivity in Ba(Fe(1-x)Co(x))2As2 for 0.060≤x≤0.071.

We present 75As nuclear magnetic resonance data from measurements of a series of Ba(Fe(1-x)Co(x))2As2 crystals with 0.00≤x≤0.075 that reveals the coexistence of frozen antiferromagnetic domains and superconductivity for 0.060≤x≤0.071. Although bulk probes reveal no long range antiferromagnetic order beyond x=0.06, we find that the local spin dynamics reveal no qualitative change across this transition. The characteristic domain sizes vary by more than an order of magnitude, reaching a maximum variation at x=0.06. This inhomogeneous glassy dynamics may be an intrinsic response to the competition between superconductivity and antiferromagnetism in this system.

NMR evidence for inhomogeneous nematic fluctuations in BaFe2(As1-xPx)2

We present evidence for nuclear spin-lattice relaxation driven by glassy nematic fluctuations in isovalent P-doped BaFe_{2}As_{2} single crystals. Both the ^{75}As and ^{31}P sites exhibit a stretched-exponential relaxation similar to the electron-doped systems. By comparing the hyperfine fields and the relaxation rates at these sites we find that the As relaxation cannot be explained solely in terms of magnetic spin fluctuations. We demonstrate that nematic fluctuations couple to the As nuclear quadrupolar moment and can explain the excess relaxation. These results suggest that glassy nematic dynamics are a common phenomenon in the iron-based superconductors.

Evolution of hyperfine parameters across a quantum critical point in CeRhIn 5

We report Nuclear Magnetic Resonance (NMR) data for both the In(1) and In(2) sites in the heavy fermion material CeRhIn

NMR evidence for inhomogeneous glassy behavior driven by nematic fluctuations in iron arsenide superconductors

_5

Local Nematic Susceptibility In Stressed BaFe 2 As 2 From NMR Electric Field Gradient Measurements

under hydrostatic pressure. The Knight shift data reveal a suppression of the hyperfine coupling to the In(1) site as a function of pressure, and the electric field gradient,

Measurements of the NMR Knight shift tensor and nonlinear magnetization in URu2Si2

\nu_{\alpha\alpha}

NMR investigation of antiferromagnetism and coherence in URu2Si2-xPx

, at the In(2) site exhibits a change of slope,

Nuclear magnetic resonance probe head design for precision strain control

d\nu_{\alpha\alpha}/dP

Optically detected magnetic resonance of nitrogen vacancies in a diamond anvil cell using designer diamond anvils

, at

Development and Calibration of a Ruby Fluorescence Pressure Measurement System

P_{c1} = 1.75