Spin-up conversion, exchange-interactions, and tailored magnetic properties in core-shell La₂NiMnO₆ of small crystallites

Abstract

La2NiMnO6—a ferromagnetic (FM) insulator offers tunable charge carriers and spins useful to devise its multiple properties and applications. In this view, we studied a core-shell La2NiMnO6 (2–3 nm shell on 65 – 80 nm core) of a Ni2+/Ni3+(d7) to Mn4+/Mn3+ (d4) spin-up conversion— revived a new FM phase-2, raising a spin-density σ s = 0.7 s a− 1 over the Ni2+/Mn4+ species (phase-1), σ s = 0.5 s a− 1, i.e. 2.12 μB /f.u. larger spin moment. HRTEM images studied with x-ray diffraction characterizing core-shell structure that plays a crucial role in tuning the high spin FM phase-2 of profound properties. Below 110 K, the dc magnetization and ac magnetic susceptibility χ(ω, T) reveal a metastable magnetic behavior on an antiferromagnetic canting of a spin-glass nature. The results follow a Vogel–Fulcher type relaxation with a relaxation time τ 0 ∼ 10−13 s, confirming a spin-glass freezing behavior. Uniquely, FM field of phase-1 controls magnetics of phase 2 of a coupled magnet, modulating joint features with small thermal magnetic hysteresis on heating-cooling cycles.

Coexistence of tetragonal and cubic phase induced complex magnetic behaviour in CoMn2O4 nanoparticles

“…The octahedral bond lengths such as (O-B) ax and (O-B) eq are found to be 2.245 (2) and 1.9781 (3) respectively for the above-reported particles of 40 nm [24]. In order to examine the reason behind the decrease in cell volume in the present case, we have determined the particle size from Williamson-Hall analysis [45]. The contribution of particle size and strain is estimated by subtracting the contributions of Kα 2 and instrumental broadening from the FWHM of the various Bragg peaks.…”

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

“…(b) and (c) Histograms of the distributions of the length and diameter of the LNMO NRs; Figure S2: Temperature dependent dielectric permittivity ( ε r ) and its reciprocal (1000/ ε r ) of the LNMO ceramics prepared from (a,b) NPs and (c,d) NRs; Figure S3: Plots of as a function of for the LNMO ceramics prepared from NPs measured at (a) 4 kHz, (b) 10 kHz, (c) 80 kHz, and (d) 100 kHz; Figure S4: Plots of as a function of for the LNMO ceramics prepared from NRs measured at (a) 4 kHz, (b) 10 kHz, (c) 80 kHz, and (d) 100 kHz; Table S1: Comparison between the magnetic data and Curie-Weiss fitting parameters of the as-synthesized LNMO samples (nanoparticles (NPs), nanorods (NRs), thin films, and bulk) and that reported in the recent literatures. References [ 83 , 84 ] are cited in Supplementary Materials.…”