0000000000265688
AUTHOR
Fl Pratt
Magnetic phase diagram of La2−xSrxCoO4 revised using muon-spin relaxation
We report the results of a muon-spin relaxation (mu SR) investigation of La2-xSrxCoO4, an antiferromagnetic insulating series which has been shown to support charge ordered and magnetic stripe phases and an hourglass magnetic excitation spectrum. We present a revised magnetic phase diagram, which shows that the suppression of the magnetic ordering temperature is highly sensitive to small concentrations of holes. Distinct behavior within an intermediate x range (0.2 <= x less than or similar to 0.6) suggests that the putative stripe ordered phase extends to lower x than previously thought. Further charge doping (0.67 <= x <= 0.9) prevents magnetic ordering for T greater than or similar to 1.…
Stripe disorder and dynamics in the hole-doped antiferromagnetic insulator La5/3Sr1/3CoO4
We report on an investigation into the dynamics of the stripe phase of La5/3Sr1/3CoO4, a material recently shown to have an hour-glass magnetic excitation spectrum. A combination of magnetic susceptibility, muon-spin relaxation and nuclear magnetic resonance measurements strongly suggest that the physics is determined by a disordered configuration of charge and spin stripes whose frustrated magnetic degrees of freedom are strongly dynamic at high temperature and which freeze out in a glassy manner as the temperature is lowered. Our results broadly confirm a recent theoretical prediction, but show that the charge quenching remains incomplete well below the charge ordering temperature and rev…