Magnetization ofLa2−xSrxNiO4+δ

Abstract

We have studied the magnetization of a series of spin-charge ordered La2−xSrxNiO 4+δ single crystals with 0 ≤ x ≤ 0.5. For fields applied parallel to the ab plane there is a large irreversibility below a temperature TF1 ∼ 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.

Hour-glass magnetic spectrum arising from a striped cluster spin-glass ground state in La1.75Sr0.25CoO<

“…27). Similar results have been found for the lightly-doped cuprates 15 and nickelates, 16 but with different exponents. Although the precise nature of the spin-glass state seems to be material dependent, it appears that spin-glass behavior is a universally shared property associated with the imperfect stripe order of real-world materials.…”

Magnetic Nature of a Ni Dopant in La1.85Sr0.15CuO4: Spin-Glass Behavior

“…In the single crystals of LSCO with x = 0.04 Sr concentration similar scaling was found, but splitting between ZFC and FC χ(T ) curves was observed both when field was applied in Cu-O planes and along c axis, perpendicular to Cu-O planes [16]. In the single crystals of La 2−x Sr x NiO 4 (LSNO) a splitting, indicative of SG behavior, was found only when field was applied parallel to the Ni-O planes and was not observed when the field was along c-axis, which strongly suggests that the SG phase has quasi-2D character and is related to frustration of the magnetic order in Ni-O planes [23]. In addition, the decay of remnant magnetization in LSCNO appeared to be not consistent with the stretched exponential formula while in LSCO was found to be well described by this expression with the parameter 1−n equal to 1/3, the value predicted by numerical simulation for 3-dimensional Ising SG [15].…”

Spin reorientation and glassy dynamics inLa1.55Sr0.45NiO4

“…The general form of the susceptibility is similar to that of other compositions. 13 A change in the slope of the susceptibility corresponds to a CO ͑Ref. 12͒ at high temperatures and a resultant SO at lower temperatures.…”

“…Charge-stripe ordering in LSNO has previously been investigated using neutrons [7][8][9][10][11][12][13] and x rays. [14][15][16] Despite a number of investigations into the charge-stripe structure, only the crystal structure has been experimentally determined.…”

“…Moreover there is a dramatic change in the functional form of the remnant magnetization around the SR temperature. 13 The purpose of this work is to further characterize the compositional doping levels up to x = 0.5, more specifically to investigate the stability of the spin stripes as the checkerboard-type order, obtained at half doping, is approached from lower doping levels. At half doping the magnetic excitation spectrum of LSNO shows additional modes to those observed at x ϳ 1 / 3.…”