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Although the bulk hexaferrites are known to exhibit strong magnetoelectric (ME) effects near room temperature, the same effects are not realized in a thin film form. Herein, the growth of nearly epitaxial Co2Z‐type hexaferrite Ba0.3Sr2.7Co2Fe24O41 (BSCFO) thin films on a SrTiO3 (111) substrate by a chemical solution deposition method is reported. The reciprocal space mapping on the annealed BSCFO films reveals broadening along the qx directions in the (0014) and (0018) peaks, indicating that the oxygen planes belonging to the off‐centered octahedra have randomly distributed out‐of‐plane tilt to indicate significant disorder in the crystallographic orientation. Quantitative investigations reveal that both ME susceptibility and modulated electric polarization (ΔP) by magnetic field up to 370 K in the BSCFO films are always larger than those of the Co2Z‐type single crystal by ≈2–15 times and further increase upon having enhanced qx broadening in the (0014) and (0018) peaks. As the off‐centered octahedral sites can be a primary source of ΔP as predicted by the p–d hybridization mechanism, these results indicate that effective off‐centering could be further enhanced by the orientational disorder. This study identifies the potential of applying the ME hexaferrite films for multifunctional devices. [ABSTRACT FROM AUTHOR]

CuCrP2S6, a van der Waals magnet having stacked layers of 2D honeycomb lattice made of CuS3 triangles and CrS6 octahedra, exhibits an A‐type antiferromagnetic order with the Néel temperature (TN) = 32 K. Upon in‐plane magnetic field (H) being applied below TN, H‐induced modulation of the c*‐axis electric polarization (ΔPc*) is found at fields lower than the saturation field µ0HS = 6.1 T, at which a forced ferromagnetic alignment sets in. Based on the symmetry analyses and dependence of ΔPc* on H and the azimuthal angle of applied H direction, a microscopic origin of the magnetoelectric (ME) coupling is attributed to the spin‐direction‐dependent p–d hybridization that is allowed due to the presence of off‐centered Cr3+ octahedra. A comparative study on CuCrP2Se6, however, finds no H‐induced P modulation due to cancellation of P between neighboring layers with the doubling of a crystallographic unit cell at TN. As the p–d hybridization mechanism allows generation of P in a single Cr atom–ligand pair, the results imply that large ME coupling should exist even in a single layer limit of CuCrP2S6. [ABSTRACT FROM AUTHOR]

We report the existence of ferromagnetic correlations (FMC) in the paramagnetic (PM) matrix of cubic La1− xSr xMnO3− δ ( x = 0.80, 0.85) well above its coupled structural, magnetic, and electronic phase transitions. The dc-magnetization versus temperature [ M( T)] behavior under different magnetic fields (from 100 Oe to 70 kOe) shows the presence of short-range magnetic correlations up to ( TFMC ∼) 365 K, far above the antiferromagnetic ordering temperatures ( TN =) 260 and 238 K for x = 0.80 and 0.85, respectively. More importantly the observed short-range FMC survive even up to 70 kOe, which indicates their robust nature. The temperature region between TN and TFMC is dominated by the presence of correlated ferromagnetic (FM) entities within the PM matrix and stabilized due to A-site chemical disorder. Our results further illustrate that for the studied compositions, the oxygen off-stoichiometry does not have any significant effect on the nature and strength of these FM entities; however, FM interactions increase in the oxygen-deficient samples. These compositions are the unique examples, where the presence of FMC is observed in an undistorted basic cubic perovskite lattice well above TN and therefore are novel to understand the physics behind the colossal magnetoresistance effect. [ABSTRACT FROM AUTHOR]

Structural phase-transition studies employing low-temperature transmission electron microscopy and low-temperature X-ray diffraction have been carried out on nearly stoichiometric ( δ = 0.01) and on off-stoichiometric ( δ = 0.12) versions of La0.2Sr0.8MnO3− δ manganite. The nearly stoichiometric La0.2Sr0.8MnO3− δ undergoes a cubic to Jahn-Teller distorted C-type antiferromagnetic tetragonal phase transition at 260 K. For off-stoichiometric La0.2Sr0.8MnO3− δ the Jahn-Teller distorted tetragonal phase transition is totally suppressed and the basic perovskite lattice remains cubic but shows a charge-ordered phase. Stabilization of charge-ordered phase in the absence of cooperative Jahn-Teller distortion has been attributed to Coulomb repulsion and Hunds coupling energy. The off-stoichiometric sample shows characteristically different physical properties. This has been realized through transport, magnetic, and calorimetric measurements. A smooth crossover from variable-range hopping transport to a power-law dependence of resistivity ( ρ) on temperature ( T), i.e., ρ = CT− α has been realized. This has been attributed to multistep inelastic tunneling through channels involving localized states around oxygen vacancy sites. [ABSTRACT FROM AUTHOR]

Structural phase-transition studies employing low-temperature transmission electron microscopy and low-temperature X-ray diffraction have been carried out on nearly stoichiometric ( δ = 0.01) and on off-stoichiometric ( δ = 0.12) versions of La0.2Sr0.8MnO3− δ manganite. The nearly stoichiometric La0.2Sr0.8MnO3− δ undergoes a cubic to Jahn-Teller distorted C-type antiferromagnetic tetragonal phase transition at 260 K. For off-stoichiometric La0.2Sr0.8MnO3− δ the Jahn-Teller distorted tetragonal phase transition is totally suppressed and the basic perovskite lattice remains cubic but shows a charge-ordered phase. Stabilization of charge-ordered phase in the absence of cooperative Jahn-Teller distortion has been attributed to Coulomb repulsion and Hunds coupling energy. The off-stoichiometric sample shows characteristically different physical properties. This has been realized through transport, magnetic, and calorimetric measurements. A smooth crossover from variable-range hopping transport to a power-law dependence of resistivity ( ρ) on temperature ( T), i.e., ρ = CT− α has been realized. This has been attributed to multistep inelastic tunneling through channels involving localized states around oxygen vacancy sites. [ABSTRACT FROM AUTHOR]