Spin reorientation transition in the incommensurate stripe-ordered phase of La3/2Sr1/2NiO4

TL;DR

This study investigates the spin ordering and reorientation in La3/2Sr1/2NiO4 using neutron diffraction, revealing a first-time observation of spin reorientation in an incommensurate stripe-ordered phase.

Contribution

It reports the first observation of spin reorientation in La2-xSrxNiO4+delta with incommensurate stripe order, expanding understanding of magnetic phase transitions in these materials.

Findings

Spin ordering occurs below 80 K with incommensurability epsilon ~ 0.445.

A spin reorientation transition occurs at approximately 57 K.

The spin axes rotate from about 52° to 78° during the transition.

Abstract

The spin ordering of La3/2Sr1/2NiO4 was investigated by magnetization measurements, and by unpolarized- and polarized-neutron diffraction. Spin ordering with an incommensurability epsilon ~ 0.445 is observed below T_so ~ 80 K. On cooling, a spin reorientation is observed at 57 +/- 1 K, with the spin axes rotating from 52 +/- 4 degrees to 78 +/- 3 degrees. This is the first time a spin reorientation has been observed in a La2-xSrxNiO4+delta compound having incommensurate stripe order.