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The single-phase bismuth ferrite BiFeO 3 (BFO) has garnered significant interest due to its spintronic-based switching properties observed at room temperature. The first-principles calculations were executed to examine the spin-polarized electronic, dielectric, and structural characteristics of co-doped BFO with lanthanum (La) at A-site and cobalt (Co), nickel (Ni) at B-site in its hexagonal phase (Bi 1-α La α Fe 1-β Ni β O 3 with α = β = 0.04) with generalized gradient approximation (GGA-PBE). The highest value (1.01 × 10−11 A) of total current observed in La Ni co-doped BFO, featuring a distinct spin current of the same magnitude, attributed to spin polarization at the Fermi level (100 %). Additionally, Co-doped BFO exhibits the highest observed spin current density (1.05 × 109A/m2) and charge current density (1.03 × 10−5A/m2). In case of dielectric switching properties, the Ni-doped BFO displays the lowest values of linear dielectric polarization (6.00 × 10−2 C/m2), polarization charge at its interface (1.27 × 10−17 C), capacitance (4.23 × 10−15 F), and switching energy (3.81 × 10−19 J), which is particularly lower than the reported switching energy (1.92 aJ) of multiferroic capacitor. [ABSTRACT FROM AUTHOR]

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In this paper, an analysis is made of the physical processes that occur in the spinvalve structures during the recording or reading of bits in high-speed magnetic memory devices using the phenomenon of moment transfer by spin-polarized current. Mathematical models of the phenomenon of magnetic resistance for magnetite / non-magnetic metal / magnet structures and phenomena that occur when the free layer is reversed under the influence of a spin-polarized current are presented. The analysis of the effect on the magnetoresistive effect of the spin-valve structure of the ratio of the thickness of the free and fixed layers are provided. The effect on the magnetoresistive effect in the spin-valve structure of the ratio of the thickness of ferromagnetic layers with small and large coercive forces (free and fixed layer) is investigated. It is shown that for high values of the polarization coefficient, the increase in the thickness of the fixed layer results in an undesired decrease in the magnetoresistive effect. [ABSTRACT FROM AUTHOR]

Highlights • A spin current generator in a single molecular magnet is realized. • The spin-related currents are studied by Hubbard operator Green’s function method. • The system can generate spin-polarized current or pure spin current. • Two configurations of spin bias are considered and they show different features. Abstract In this paper we study the spin- and charge-transport behaviors of a single molecular magnet (SMM) coupled to external reservoirs with spin-dependent chemical potentials. By using the Hubbard operator Green’s function method, we show that in the limit of a pinned macrospin the SMM can serve as an effective spin current filter or generator. Two configurations of spin bias are considered. For SMM coupled with symmetric dipolar spin bias, the system can generate spin-polarized current and pure spin current by adjusting the relative magnitude of spin bias and Coulomb interaction. It originates from the competition of two spin-opposite transport channels. Also due to this competition, one can observe a negative differential spin conductance. For SMM coupled with asymmetric dipolar spin bias, the system can only generate spin-polarized currents. The SMM as a spin current generator shows features different from the usual quantum dot system and these features can be useful in molecular spintronics. [ABSTRACT FROM AUTHOR]