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The structural, mechanical, electronic, and magnetic properties of the new series of Co-based Equiatomic Quaternary Heusler Alloys (EQHAs) XX'YZ (X = Co; X' = Zr, Ru; Y = Ti, V; Z = Sn, Al, Ga, Si, Ge) have been calculated using first-principles calculations. The Full Potential-Linearized Augmented Plane Wave (FP-LAPW) approach was used in association with Density Functional Theory (DFT). We treated the exchange-correlation (XC) energy functional using a Generalized Gradient Approximation (GGA) in the Perdew-Burke-Ernzerhof (PBE) scheme. We included the TB-mBJ potential (GGA-mBJ) and the Hubbard correction (GGA + U) to improve the precision of the band gap values. Spin-orbit coupling (GGA-SOC) calculations are required due to the existence of heavier elements such as Zr and Ru. We have included the GGA-SOC calculations to estimate the total and partial magnetic moment and their impact on the electronic structure of Co-based EQHAs. The ground state parameters of proposed Co-based EQHAs were determined, including the lattice parameter, total energy, bulk modulus, and its derivative. The electronic structure of these materials revealed the presence of half-metallic ferromagnetism and spin-gapless semiconductor behavior. In addition, the origin of the band gap in spin channels was also investigated. In addition, we employed the mean-field approximation (MFA) method based on the Heisenberg model to determine the Curie temperature (T C). This theoretical analysis adds a new level of sophistication to the application of Co-based EQHAs in spintronic applications. [Display omitted] [ABSTRACT FROM AUTHOR]

We report the results of detailed investigations on structural and magnetic properties of polycrystalline GdFeO 3 compound. Temperature-dependent magnetization studies support an antiferromagnetic transition at T N (Gd3+) ∼ 2.8 K associated with Gd3+ spins. A clear spin-flop type metamagnetic transition associated with Gd3+ sub-lattice is observed in field-dependent magnetization measurements made across T N (Gd3+). The compound also shows a weak hysteresis behaviour linked to canted Fe3+ moments near-zero field region, with a remnant magnetization of ∼0.022 μ B. • Low-temperature magnetization measurements of polycrystalline GdFeO 3. • Metamagnetic Transition in GdFeO 3. • Plausible ground state spin structure of GdFeO 3. • Weak ferromagnetic behaviour due to Dzyaloshinskii–Moriya interaction in GdFeO 3. [ABSTRACT FROM AUTHOR]

Abstract: Present study reports the detailed structural and magnetic, as well as chemical analysis of polycrystalline Zn1− x Mn x O (where x=0, 0.005, 0.01, 0.03, 0.05 and 0.1) samples synthesized by the high-temperature solid state reaction route. X-ray diffraction studies reveal the presence of secondary phase for higher Mn-doping concentrations (x≥0.03). Secondary phase formation having spinel structure is confirmed and reported as an evidence for the first time using transmission electron microscopy study. Chemical investigations using X-ray photoelectron spectroscopy showed the presence of Mn in two valence states. From the observed results we are of the opinion that Zn2+ ions, mainly present at or near grain boundaries, diffuse into manganese oxide to form a stable spinel phase Zn x Mn3− x O4 at or near the grain boundaries of ZnO/Zn1− x Mn x O. Magnetization measurements did not show any magnetic transition down to 5K. [Copyright &y& Elsevier]

• Non-covalent charge transfer interaction between GO and CuPc. • CuPc aggregation change from J to H state, GO stacking increases. • Charge transfer interaction modifies magnetic property of GO. • Spin angular momentum of GO is inferred to be reduced on interaction with CuPc. • Improvement in optical limiting behaviour in nanocomposites due to increased stacking of GO. Investigations on the non-covalent, charge transfer interaction between graphene oxide (GO) sheets and unsubstituted copper phthalocyanine (CuPc) revealed their mutual influence on their structural, optical and magnetic properties. While charge transfer interaction is found to change the aggregation of CuPc from J to H state, and this change increasing with GO concentration, the aggregation/stacking of GO is also found to be getting modified (increasing in this study) on interaction with CuPc. The charge transfer interaction is suggested to be mostly occurring through carboxyl groups at the edges of GO sheets, which could be causing this stacking/aggregation change of GO. While GO, CuPc and the nanocomposites exhibited paramagnetic behaviour, the saturation magnetization of the nanocomposites is observed to be lower than that expected. This is correlated to the reduction in the total spin (J) of GO and its subsequent altered magnetic response, which is attributed to the charge transfer interaction with CuPc. This study shows the possibility of tuning the magnetic properties of GO through such non-covalent, charge transfer routes. The improved optical limiting behaviour of the nanocomposites is further attributed to the charge transfer interaction and the increase in stacking of GO. [ABSTRACT FROM AUTHOR]