Structural and critical magnetic behavior in polycrystalline Sm0.47La0.20K0.33MnO3 manganite prepared via solid-state reaction.

The Sm0.47La0.20K0.33MnO3 perovskite manganite was synthesized using the solid-state reaction method and its structural, magnetic, and critical properties were investigated. This work analyzed the structural characteristics of our sample through Rietveld refinement of the X-ray diffraction pattern and Hirshfeld surface mapping (HS) techniques. It was shown that the sample crystallized in the space group Pnma, with the lattice parameters: a = 5.461 (4) Å, b = 5.478(1) Å, and c = 7.706(8) Å. The Mn–O bond length ~ 1.9 Å obtained from the Rietveld refinement, agrees with the minimum distances between Mn and O atoms obtained from the characteristic 2D fingerprint plots of this manganite. From M vs. T measurements in the range of 5 K < T < 300 K and isothermal measurements M (H) in the range of 0 T < H < 6.5 T , two phase transitions were observed: (i) a paramagnetic (PM)—ferromagnetic (FM) second-order phase transition, and (ii) a FM—spin-glass-like transition. The latter is associated with the presence of samarium in the crystalline structure of the manganite studied. Furthermore, a collective freezing state occurs at T B = 72.83 K . The behavior of the inverse of susceptibility χ - 1 (T) vs. T shows the coexistence of FM clusters within the PM state ( T > 184 K ). Modified Arrott plots (applied to 3D-Heisenberg, 3D-Ising, and Tricritical mean-field models), as well as the Kouvel-Fisher method, were employed to obtain the critical coefficients that were found to be β = 0.367 , γ = 1.330 , and δ = 4.776 for the Sm0.47La0.20K0.33MnO3 manganite. It was confirmed that both critical exponents (β and γ) satisfy the Widom scaling relation (δ = 1 + γ β) . However, a slight deviation from the theoretical values exists of the critical exponent δ obtained with the 3D Heisenberg model. This may be due to the nanoscale dimensions of the secondary phase KMn 2 O 6 particles. In conclusion, critical coefficients and observed phase transitions are significant because they provide guidance for theoretical modeling, enabling real-world applications in diverse technical domains, and shed light on material behavior, all of which contribute to our understanding of manganites. Based on the results of the search, it appears that a better understanding of the critical magnetic behavior in polycrystalline manganites may greatly improve future research and applications in the following areas: Hard disk drives HDDs and magnetic tapes are magnetic data storage devices which can benefit from manganite research to be advanced. Spintronics is a technology, which is based on electron spin polarization mechanism to process information. It utilizes manganites as an important material. [ABSTRACT FROM AUTHOR]