Stripes in La2NiO4.17: charge and spin ordering according to NMR

TL;DR

This study uses 139La NMR to investigate charge and spin stripe ordering in La2NiO4.17, revealing site-centered stripes, spin freezing transitions at 180 K and 50 K, and differences from neutron data in disordered nickelates.

Contribution

It provides detailed NMR insights into stripe order and spin freezing in La2NiO4.17, highlighting differences from previous neutron studies in disordered samples.

Findings

Charge and spin stripes are site centered.

Domain spins freeze at approximately 180 K.

Additional spin freezing occurs at around 50 K.

Abstract

Charge and spin ordering in La2NiO4.17 has been studied by 139La NMR using the field and temperature dependence of the linewidth and relaxation rates. The stripes are site centered and the domain spins freeze at ~ 180 K, followed by a second transition at ~ 50 K, where the spins on the domain walls freeze. Although consistent with the neutron measurements, the results are quantitatively different from the NMR results in a nickelate with quenched Sr disorder.