Passive control of nanoparticles in stagnation point flow of Oldroyd-B nanofluid with aspect of magnetic dipole

The present research focuses on nanoparticle suspensions and flow properties in the context of their applications. The application of these materials in biological rheological models has piqued the attention of many researchers. Magneto nanoparticles have an important function in controlling the viscoelastic physiognomies of ferrofluid flows. Having such substantial interest in the flow of ferroliquids our vision is to discuss the stagnation point flow of ferromagnetic Oldroyd-B nanofluid through a stretching sheet. The Buongiorno nanofluid model with Brownian motion and thermophoretic properties is examined. A chemical reaction effect and porous medium is also taken into account. Moreover, the modelled equations are changed to ordinary differential equations (ODEs) using suitable similarity transformations. Which are then solved using classical Runge-Kutta (RK) process with shooting technique. The solutions for the flow, thermal, concentration, skin friction, rate of heat and mass transfer features are attained numerically and presented graphically. The significant results of the current study are that, the growing values of ferromagnetic interaction parameter and porosity parameter declines the velocity profile. The rising values of chemical reaction rate parameter and Brownian motion parameter declines the mass transfer but inverse behaviour is seen for augmented values of thermophoresis parameter.

Magnetic and resonance properties of the Y0.5Sr0.5Cr0.5Mn0.5O3 polycrystal

The magnetostatic and magnetic resonance properties of the Y0.5Sr0.5Cr0.5Mn0.5O3 polycrystalline system have been experimentally studied. The intracrystalline ferromagnetic interaction turned out to be prevalent while the intercrystalline interaction appears to have antiferromagnetic character. We found that two absorption lines are observed in the spectrum in the magnetic ordering region at T < 80 K. The high-field line corresponds to the interacting parts of polycrystal related to the disordered shells and the low-field peak is system of ferromagnetic particles.

Two-Dimensional Nitronyl Nitroxide–Cu Networks Based on Multi-Dentate Nitronyl Nitroxides: Structures and Magnetic Properties

Two multi-dentate nitronyl nitroxide radicals, namely, bisNITPhPy ([5-(4-pyridyl)-1,3-bis(1′-oxyl-3′-oxido-4′,4′,5′,5′-tetramethyl-4,5-hydro-1H-imidazol-2-yl)]benzene) and NIT-3Py-5-4Py (2-{3-[5-(4-pyridyl)]pyridyl}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were assembled with CuII ions to obtain two-dimensional heterospin 2p–3d coordination polymers [Cu7(hfac)14(bisNITPhPy)2]n (1) and [Cu2(hfac)4(NIT-3Py-5-4Py)]n (2) (hfac: hexafluoroacetylacetonate). In both compounds, the bisNITPhPy and NIT-3Py-5-3Py radicals acted as pentadentate and tetradentate ligands, respectively, to connect with CuII ions, generating a 2D layer structure. The analysis of the magnetic behavior indicated that strong antiferromagnetic coupling and ferromagnetic interaction (J = 17.1 cm−1) coexisted in 1. For 2, there were ferromagnetic couplings between the CuII ion and NO group, as well as the CuII ion and radical via the pyridine ring with J1 = 32.8 and J2 = 2.2 cm−1, respectively.

A new family of Fe4Ln4 (Ln = DyIII, GdIII, YIII) wheel type complexes with ferromagnetic interaction, magnetocaloric effect and zero-field SMM behavior

Observation of ferromagnetic interactions and single molecule toroic (SMT) behavior in Fe4Ln4 wheel complexes.

Magnetism in a helicate complexes arising with the tetradentate ligand

The synthesis of [M(dimphen)(NCS)2] (MII = Fe (1), Co (2), Mn (3)) and [Fe(dimphen)(NCSe)2] (4), where dimphen = [1,2-bis(9-methyl-1,10-phenanthrolin-2-yl)ethane], are reported. 1 shows ferromagnetic interaction, and 2 displays single-molecular magnet behaviour.

Theoretical Study on Magnetic Interaction in Pyrazole-Bridged Dinuclear Metal Complex: Possibility of Intramolecular Ferromagnetic Interaction by Orbital Counter-Complementarity

A possibility of the intramolecular ferromagnetic (FM) interaction in pyrazole-bridged dinuclear Mn(II), Fe(II), Co(II), and Ni(II) complexes is examined by density functional theory (DFT) calculations. When azide is used for additional bridging ligand, the complexes indicate the strong antiferromagnetic (AFM) interaction, while the AFM interaction becomes very weak when acetate ligand is used. In the acetate-bridged complexes, an energy split of the frontier orbitals suggests the orbital counter-complementarity effect between the dxy orbital pair, which contributes to the FM interaction; however, a significant overlap of other d-orbital pairs also suggests an existence of the AFM interaction. From those results, the orbital counter-complementarity effect is considered to be canceled out by the overlap of other d-orbital pairs.

Магнитные и резонансные свойства поликристалла Y-=SUB=-0.5-=/SUB=-Sr-=SUB=-0.5-=/SUB=-Cr-=SUB=-0.5-=/SUB=-Mn-=SUB=-0.5-=/SUB=-O-=SUB=-3-=/SUB=-

The magnetostatic and magnetic resonance properties of the Y_0.5Sr_0.5Cr_0.5Mn_0.5O_3 polycrystalline system have been experimentally investigated. The predominance of the intracrystalline ferromagnetic interaction and the antiferromagnetic character of the intercrystallite interaction have been established. The magnetic resonance spectrum in the magnetically ordered region consists of two lines. The high-field line corresponds to the interacting parts of polycrystal shells and the low-field peak is related to the disordered system of ferromagnetic particles.