Magnetization of La(2-x)Sr(x)NiO(4+ delta) (0 < x < 0.5) and observation of novel memory effects

TL;DR

This study investigates the magnetization properties of La(2-x)Sr(x)NiO(4+delta) crystals, revealing large irreversibility, a novel memory effect in thermo-remnant magnetization, and temperature-dependent spin reorientation phenomena.

Contribution

It reports the discovery of a new memory effect in thermo-remnant magnetization across a range of doping levels in La(2-x)Sr(x)NiO(4+delta) and details its relation to spin reorientation transitions.

Findings

Large irreversibility below ~50 K for fields in the ab plane

Memory of the temperature at which the external field was removed

Increase in thermo-remnant magnetization through spin reorientation transition

Abstract

We have studied the magnetization of a series of spin-charge ordered La(2-x)Sr(x)NiO(4+delta) single crystals with 0 < x < 0.5. For fields applied parallel to the ab plane there is a large irreversibility below a temperature T(F1) ~ 50 K and a smaller irreversibility that persists up to near the charge ordering temperature. We observed a novel memory effect in the thermo-remnant magnetization across the entire doping range. We found that these materials retain a memory of the temperature at which an external field was removed, and that there is a pronounced increase in the thermo-remnant magnetization when the system is warmed through a spin reorientation transition.