NMR Study of MnSi under Pressure.

2 3 Fe b 19 98 NMR Study of MnSi under Pressure

The magnetic phase diagram Tc(P ) of the weak itinerant helimagnetic compound MnSi is reviewed upon a Nuclear Magnetic Resonance (NMR) experiment. We present a systematic study on the evolution of the NMR spin echo signal at T = 1.4 K of the non-magnetic silicone sites, Si, up to 17.8 kbar. The pressure effect is interpreted as a weak variation of the local electronic spin polarization and the ...

Unusual Hall effect anomaly in MnSi under pressure.

We report the observation of a highly unusual Hall current in the helical magnet MnSi in an applied pressure P=6-12 kbars. The Hall conductivity displays a distinctive stepwise field profile quite unlike any other Hall response observed in solids. We identify the origin of this Hall current with the effective real-space magnetic field due to chiral spin textures, which may be a precursor of the...

NMR investigation of superconductivity and Antiferromagnetism in CaFe2As2 under pressure.

We report 75As NMR measurements in CaFe2As2, made under applied pressures up to 0.83 GPa produced by a standard clamp pressure cell. Our data reveal phase segregation of paramagnetic and antiferromagnetic (AFM) phases over a range of pressures, with the AFM phase more than 90% dominant at low temperatures. In situ rf susceptibility measurements indicate the presence of superconductivity. 75As s...

First Principles Study of Tetracene under Pressure

First-principles study of CaFe2As2 under pressure

We perform first-principles calculations on CaFe2As2 under hydrostatic pressure. Our total-energy calculations show that though the striped antiferromagnetic (AFM) orthorhombic (OR) phase is favored at P = 0, a nonmagnetic collapsed tetragonal (cT) phase with diminished c parameter is favored for P > 0.36 GPa, in agreement with experiments. Rather than a mechanical instability, this is an entha...