Influence of zinc substitution on structural, elastic, magnetic and optical properties of cobalt chromium ferrites

The polycrystalline Co1−xZnxCr0.5Fe1.5O4 series with (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) has been synthesized by conventional ceramic rout method. The structural and elastic properties have been investigated by X-ray diffractometer and Fourier transform spectroscopy. Both XRD and FTIR confirm the formation of single phase cubic spinel ferrites. The cationic distribution for all samples has been proposed. The lattice parameter, X-ray density, hoping length, bond length, and packing factors–in accompaniment with variations in the zinc concentration–have been studied. The IR band position has been explained by the cations involved in the structure. The elastic moduli such as Young's modulus, bulk modulus, rigidity modulus and Poison's ratio have bee calculated using force constants. Scanning electron microscope (SEM) observation conveys information about the agglomeration of particles. The hysteresis curve obtained from vibrating sample magneto meter (VSM) conveys information about the soft nature of prepared compositions. The saturation magnetization decreases with addition of zinc ions and coercivity is almost zero. An increase in band gap energy has been observed with addition of zinc by Ultraviolet Visible Spectroscopy (UV-VIS), which is due to small crystallite size.

Magnetic nanoparticles for components of MRI diagnostics and electronic devices

The formation of single-phase solid solutions of iron oxide and manganese oxide with a spinel structure in MnxFe3 – xO4 system (x = 0; 0.3; 0.6; 0.8; 1.0; 1.2; 1.4; 1.8) has been established by methods of X-ray phase analysis and infrared spectroscopy. The maximum saturation magnetization was found for the composition Mn0.3 Fe2.7O4 (Ms = 68 A ⋅ m2 ⋅ kg−1 at 300 K and Ms = 85 A ⋅ m2 ⋅ kg−1 at 5 K), which is associated with a change in the cationic distribution over tetrahedral and octahedral voids. The materials obtained were stabilized in the form of colloidal solutions using a number of polyelectrolytes. It was found that poly(diallyldimethylammonium chloride) (PDDA) had the best stabilizing effect due to its structural features. A method for controlling the magnetic properties of magnetite by partial replacement of iron ions in the magnetite structure with manganese is proposed. Changing the magnitude of the magnetization and coercive force is possible by changing the degree of substitution. Relatively high values of specific magnetization, as well as uniformity of magnetic particles in size, can be of practical interest, for the manufacture of contrast agents in MRI diagnostics.

Explaining the physiological cationic distribution in erythrocytes: The murburn perspective

Living cells are characterized by the interesting disparity in the distribution of monovalent and divalent cations, as per the order: K+ > Na+ > Mg2+ >> Ca2+. Classical biologists attribute this to energy-expended and affinity-driven processes mediated by membrane-embedded proteins. Independent physicists had proposed ionic adsorption at various interfaces and/or differences in hydration shell characteristics of the ions as the reasons for the same Herein, human erythrocytes are considered as a simple ‘living cell’ model. Energy metabolism-based outcomes (murburn equilibriums) and the dissolved-phase proteins’ innate ability to bind/adsorb ions selectively are suggested as the integral rationale for the observed phenomenon.