Structural and magnetic properties of La0.7Sr0.3Mn1−xNixO3 (x ≤ 0.4)

Abstract

We have studied the structural and magnetic properties of La0.7Sr0.3Mn1−xNixO3 (x = 0.05, 0.1, 0.20, 0.30, and 0.40) perovskites using x-ray and neutron diffraction and magnetic measurements. Our data consist of neutron (λ = 1.479 Å) and x-ray (λ = 1.5481 Å; Cu Kα) powder diffraction and magnetization measurements. We previously suggested these systems transition from ferromagnetic to antiferromagnetic ordering with the intermediate concentrations containing coexisting domains of ferromagnetically and antiferromagnetically ordered states. Upon further detailed examination, we find that the samples are homogeneous and that neutron data can be fitted to a single long-range magnetically ordered state. The compositional dependent changes are driven by a shift in the dominant near neighbor interaction from ferromagnetic to antiferromagnetic. In the intermediate compositions, peaks previously identified as due to antiferromagnetic ordering, in fact arise from charge ordering; the system remains in a ferromagnetic state where the Ni moments are antiparallel to the Mn moments. This interpretation supersedes multiphase and spin glass models for these complex systems.

Structural, Magnetic and Transport Properties of B-Site Substituted Perovskite La0.7Sr0.3MnO3

“…All systems exhibit layered magnetic behavior, a reduction in ferromagnetism with increasing transition metal content, complex magnetic interactions well below T C , and a metal to insulator transition around x~0.2 (a value also near the percolation threshold described in many works of around x~0.16). Our data for the Ni [7,9] and Cr [8] systems strongly suggest the onset of charge ordering occurs coincident with the metal to insulator transition, and not only at specific nodal quantities. We suggest this type of ordering is highly likely in the remaining transition metal-substituted systems, but that additional analysis with neutron data is needed.…”

“…As a result, a sudden drop of the magnetization has occurred, giving rise to a jump in the hysteresis curve. The La 0.7 Sr 0.3 Mn 1-x Cr x O 3 (0<x<0.6) have been prepared and influence of the Cr 3+ substitution for Mn 3+ was investigated [7,8,9]. At low temperature with small x, the net ferromagnetic behavior of the system is due to the large quantities of Mn 3+ -O-Mn 4+ ferromagnetic double exchanges taking place while the system is being driven towards a layered ferromagnetic structure by the…”

Magnetic and electrical transport properties of perovskite manganites Pr0.6Sr0.4M xMn1-xO3 (M = Fe, Co, Ni)

“…Sun et al 12 studied the magnetic and MR properties of La 0.67 Sr 0.33 Cr x Mn 1-x O 3 and observed that Cr substituted for Mn can result in a ferromagnetic interaction between Mn and Cr, similar to a double exchange. Creel et al 13 prepared La 0.7 Sr 0.3 Mn 1-x Ni x O 3 (0≤x≤0.4) via a solid state reaction and concluded that the Ni 3+ moments aligned antiferromagnetically with respect to the Mn 3+ moments. Harada et al 14 and Yoshimatsu et al 15 investigated Co-doped Pr 0.8 Ca 0.2 MnO 3 perovskite manganite samples and assumed the presence of ferromagnetic coupling between Co 2+ and Mn 4+ ions.…”