Influence of Cation Order and Valence States on Magnetic Ordering in La₂Ni_1−xMn_1+xO₆

Abstract

Among multifunctional double perovskite oxides, La2NiMnO6 has recently drawn significant attention due to its importance both in terms of understanding of fundamental physics and potential for device applications. The relative alteration in Ni:Mn ratio strongly influences the structural and magnetic properties of La2NiMnO6. The cation ratio and degree of cation order significantly affect the magnetic coupling of the two B‐site cations in these compounds. In the present study, La2Ni1−xMn1+xO6 (x = −0.25, 0, 0.25) samples with different Ni:Mn ratio have been prepared using sol–gel method and modifications of the above physical properties from that of a stoichiometric sample of La2NiMnO6 are discussed. The crystalline structures of the samples varied with different ionic ratios. While all samples exhibited ferromagnetic behavior, long‐range Ni/Mn magnetic ordering was detected in selected samples only. The experimental values of saturation magnetization were smaller than the theoretical spin‐only moments, which suggests a less ordered state for all samples. Due to an increased antiferromagnetic interaction caused by antisite disorders, the saturation magnetization decreases while the coercive field increases with decreasing Mn content.

Cluster spin-glass-like dynamics in Mn-rich La2Ni0.5Mn1.5O6 ferromagnetic insulator

“…The first derivatives of the Mn spectra are shown as the inset of figure 4(b). The Mn K XANES spectrum of the present compound is similar to those recorded for La 2 Ni 1−x Mn 1+x O 6 (x = 0.25) [30]. The Mn K absorption edge was found to lie in between those of the standard Mn 2 O 3 and MnO 2 [31].…”

Substitutional effect of Mg2+ on structural and magnetic properties of La2MgxNi1‐xMnO6 double‐perovskite thin films

“…It should be noted that the valence state of the magnetic ions at B‐sites plays an important role in optimizing the magnetic properties of double‐perovskites 18,38,40 . In terms of LNMO compounds, the Mn 4+ is beneficial for improving the ordering degree, which will lead to high magnetization saturation and good magnetic properties 41,42 .…”

“…Secondly, the RSM asymmetry (103) planes of the LM x NMO thin films are scanned to obtain the stress/strain information in the films, [34][35][36][37][38] as described in Figure 2(b-f). The (103) peak positions of all the films are located below that of the LAO substrate, indicating that these films are under in-plane compressive stress.…”

“…It should be noted that the valence state of the magnetic ions at B-sites plays an important role in optimizing the magnetic properties of double-perovskites. 18,38,40 In terms of LNMO compounds, the Mn 4+ is beneficial for improving the ordering degree, which will lead to high magnetization saturation and good magnetic properties. 41,42 Therefore, in order to reveal the valence state of Mn ions in the LM x NMO thin films, XPS spectra is employed and the patterns are further fitted by XPS Peak Fitting Program (XPSPEAK 41), as presented in Figure 4(a)-(e).…”

Unraveling the Structural, Dielectric, Magnetic, and Optical Characteristics of Nanostructured La2NiMnO6 Double Perovskites

“…However, both of them could co-exist in a large temperature range, covering room temperature [ 18 ]. The saturation magnetization ( M S ), T C , and evolution of other phases like spin-glass in the LNMO are dependent upon the cation ordering and cation valences, which are significantly influenced by the synthesized conditions [ 19 , 20 , 21 ]. Actually, in the published literature different temperature dependent magnetic properties of the LNMO under field-cooled (FC) and zero-field cooled (ZFC) modes are reported by several research groups [ 22 , 23 , 24 , 25 ].…”