Evidence of a canted magnetic state in self-doped LaMnO_3+δ(δ = 0.04): a magnetocaloric study

Abstract

We report a detailed investigation of the magnetocaloric properties of self-doped polycrystalline LaMnO(3+δ) with δ = 0.04. Due to the self-doping effect, the system exhibits a magnetic transition from a paramagnetic to ferromagnetic-like canted magnetic state (CMS) at ~120 K, which is associated with an appreciably large magnetocaloric effect (MCE). The CMS is an inhomogeneous magnetic phase developing due to a steady growth of antiferromagnetic correlation in its predominant ferromagnetic state below ∼120 K. The stabilization of CMS in this material is concluded from a comprehensive analysis of magnetocaloric data using Landau theory, which is in excellent agreement with our neutron diffraction study. The magnetic entropy change versus temperature curves for different applied fields collapse into a single curve, revealing a universal behavior of MCE. Our studies suggest that investigation of MCE is an effective technique to acquire fundamental understanding about the basic magnetic structure of a system with complex competing interactions.

Crystal structure, magnetic and dielectric behavior of h-LuMn O3± ceramics (0.95≤x≤1.04)

“…The corresponding average rate of change of T N with the Y/Mn ratio being ΔT N /Δx = 60.5 K.mol -1 Mn. Such changes of T N are coupled to the very large decrease of -98 K in Curie-Weiss temperature from x L = 0.95 to x=1 with an additional decrease of -212 K from x = 1 to x H  1.08 [15,17], yielding the average rate of change Δθ CW /Δx = -2409 K.mol -1 Mn. The analysis of the dependences of T N and θ CW on x of the data of the LuMn x O 3±δ samples in Table 1 appearance of a magnetic cusp below T N for ZFC magnetic susceptibility.…”

“…Although, upon doping or changing synthesis conditions, one is able to change the ferroic properties, still from all these experimental adjustments and theoretical approaches the role of rare-earth and metal ions on unit cell parameters and magnetic and dielectric properties could not be clearly and explicitly figured out. It was found in perovskite materials like LaMnO 3±δ that creating offstoichiometric A-site or B-site compositions would be a suitable tool for exploring the role of rare-earth (A-site) and transition metal ions (B-site) and of their effect upon the change in properties [13][14][15][16][17][18]. However, such concept has been seldom used to set the role of R and Mn ions in hexagonal rare-earth manganites [19][20][21][22].…”

Magnetic and universal magnetocaloric behavior of rare-earth substituted DyFe0.5Cr0.5O3

“…Power laws and universal scaling have been extensively used to investigate MCE in magnetic materials [15,[25][26][27][28][29][30]. [27][28][29], and inverse MCE [26].For IMCE, in compounds where symmetrical peak is observed, rescaling in T axis is not required. But in these mixed metal oxides symmetrical peak is not observed and a universal curve is not obtained.…”

Enhanced Catalytic and Photocatalytic Degradation of Organic Pollutant Rhodamine‐B by LaMnO3 Nanoparticles Synthesized by Non‐Aqueous Sol‐Gel Route

“…When the size of the magnetic particles reduces to the nanometer scale, various magnetic properties such as Curie/Neel temperature, coercivity, and saturation magnetization start showing significant changes as compared to the bulk values . The magnetic properties of stoichiometric and non‐stoichiometric LaMnO 3 nanoparticles have been reported by many researchers …”