Impact of vacancy and Na substitutions on the critical magnetic behavior in polycrystalline La0.8Pb0.2MnO3

Critical Behavior Near the Paramagnetic to Ferromagnetic Phase Transition Temperature in Sr1.5Nd0.5MnO4 Compound

“…Among the fundamental questions which remain controversial is the universality class related to the paramagnetic (PM) to ferromagnetic (FM) transition in manganites [8][9][10]. The universality class does not depend on microscopic details of the system but only on global information such as the dimension of the order parameter and space.…”

Effects of non magnetic aluminum Al doping on the structural, magnetic and transport properties in La0.57Nd0.1Sr0.33MnO3 manganite oxide

“…The process reported in the literature most often is the doping of manganites with various elements in two different positions. These are called A-site [15][16][17] and B-site (or Mn-site) [18][19][20][21][22] substitution. It is believed that the study of the doping effects at the Mn site by other elements with different valences, electron configuration, ionic radius, and non-magnetic ions is very important because of the crucial role of Mn ions in the CMR materials.…”

Critical Behavior of Ti Doping La0.57Nd0.1Pb0.33Mn1−x Ti x O3 Perovskite System

“…On the other hand, the universality class of the magnetic phase transition depends on the range of the exchange interaction J (r) in homogeneous magnets [24,25]. The long-range attractive interactions decay as [25] J (r) ≈ 1/r −(d+σ ) (10) where d is the spatial dimension, σ > 0. For a threedimensional material (d = 3), there holds the relation J (r) ≈ 1/r −(3+σ ) with 3/2 ≤ σ ≤ 2.…”

“…However, the theoretical calculations based on simplified DE models, reveal that the FM-PM transition in CMR manganites should belong to the Heisenberg universality class [8]. By contrast, the experimental estimates for critical exponents are still controversial including those for short-range Heisenberg interaction [9,10], the meanfield values [11], and those which cannot be classified into any universality class ever known [12]. Hence, the critical properties of the paramagnetic-ferromagnetic phase transition in manganites pose an important fundamental problem.…”