Magnetoelectric Effect in a Two-Layer Ferromagnetic-Piezoelectric System

Russian Physics Journal - The theory of the direct magnetoelectric (ME) effect in a two-layer ferromagnetc-piezoelectric structure that differs from the existing theories by the exact accounting of...     

Specific Heat of a Two-Layer Magnetic Superlattice

The specific heats of both a two-layer ferromagnetic superlattice and a two-layer ferrimagnetic one are studied. It is found that the spin quantum numbers, the interlayer and intralayer exchange couplings, the anisotropy, the applied magnetic field, and the temperature all affect the specific heat of these superlattices. For both the ferromagnetic and ferrimagnetic superlattices, the specific heat decreases with increasing the spin quantum number, the absolute value of interlayer exchange coupling, intralayer exchange coupling, and anisotropy, while it increases with increasing temperature at low temperatures. When an applied magnetic field is enhanced, the specific heat decreases in the twolayer ferromagnetic superlattice, while it is almost unchanged in the two-layer ferrimagnetic superlattice at low field range at low temperatures.     

Specific Heat of a Two-Layer Magnetic Superlattice

The specific heats of both a two-layer ferromagnetic superlattice and atwo-layer ferrimagnetic one are studied. It is found that the spin quantumnumbers, the interlayer and intralayer exchange couplings, the anisotropy,the applied magnetic field, and the temperature all affect the specificheat of these superlattices. For both the ferromagnetic and ferrimagneticsuperlattices, the specific heat decreases with increasing the spin quantumnumber, the absolute value of interlayer exchange coupling, intralayerexchange coupling, and anisotropy, while it increases with increasingtemperature at low temperatures. When an applied magnetic field is enhanced, the specific heat decreases in the two-layer ferromagnetic superlattice, while it is almost unchanged in the two-layer ferrimagnetic superlattice at low field range at low temperatures.     

Magnetoelectric Effect in CoFeB/MgO/CoFeB Magnetic Tunnel Junctions

JETP Letters - The possibility of electrical control of the interlayer exchange interaction in CoFeB/MgO/CoFeB tunnel junctions exhibiting magnetoresistance of ~200% is studied. It is shown that...     

Effective Dielectric Response of Composites with Graded Material

The effective dielectric response of linear composites containing graded material is investigated under an applied electric field E₀. For the cylindrical inclusion with gradient dielectric function, ε_i(r)=b+cr, randomly embedded in a host with dielectric constant ε_m, we have obtained the exact solution of local electric potential of the composite media regions, which obeys a linear constitutive relation D=εE, using hypergeometric function. In dilute limit, we have derived the effective dielectric response of the linear composite media. Furthermore, for larger volume fraction, the formulas of effective dielectric response of the graded composite media are given.     

Dynamic Effects in a Magnetic Fluid with Microdrops of Concentrated Phase in a Rotating Magnetic Field

Technical Physics - Variation in the shape of microdrops of a highly concentrated magnetic colloid resulting from phase separation in a magnetic fluid has been studied. It has been found that even...     

Chiral Magnetic Effect and Chiral Phase Transition

We study the influence of the chiral phase transition on the chiral magnetic effect. The azimuthal charge-particle correlations as functions of the temperature are calculated. It is found that there is a pronounced cusp in the correlations as the temperature reaches its critical value for the QCD phase transition. It is predicted that there will be a drastic suppression of the charge-particle correlations as the collision energy in RHIC decreases to below a critical value. We show then the azimuthal charge-particle correlations can be the signal to identify the occurrence of the QCD phase transitions in RHIC energy scan experiments.     

Effect of a Substrate on the Magnetoelectric Effect in Rare-Earth-Doped Bismuth Iron Garnet

JETP Letters - The mechanism of relaxation of the electric polarization in thin films of rare-earth-doped bismuth iron garnet on glass and gallium gadolinium garnet substrates is determined in...     

Magnetoelectric Effect in a Paramagnetic Region in Gd0.15Mn0.85Se

Physics of the Solid State - The electric polarization in a zero magnetic field and in a magnetic field of 12 kOe is measured in a GdxMn1 – xSe solid solution in the...     

Effect of a Soft Magnetic Phase on the Processes of Magnetization Reversal of a Hard/Soft Magnetic Bilayer

Physics of the Solid State - Magnetization reversal of a hard/soft magnetic bilayer in an external magnetic field has been studied by the Monte Carlo method. The magnetization reversal curves of a...     

Nonreciprocity of Propagation of Exchange-Dipole Spin Waves in Two-Layer Magnetic Films with Crossed Magnetization of the Layers

Journal of Experimental and Theoretical Physics - An analytical theory of propagation of exchange-dipole spin waves (SWs) in two-layer dipole-coupled magnetic films is presented in the...     

Effect of a Magnetic Field on the Phase Transitions in the Heisenberg Model on a Triangular Lattice

Physics of the Solid State - The phase transitions, magnetic and thermodynamic properties of a three-dimensional antiferromagnetic Heisenberg model on a layered triangular lattice in a magnetic...     

Pattern Synchronization in a Two-Layer Neuronal Network

Pattern synchronization in a two-layer neuronal network is studied. For a single-layer network of Rulkov map neurons, there are three kinds of patterns induced by noise. Additive noise can induce ordered patterns at some intermediate noise intensities in a resonant way; however, for small and large noise intensities there exist excitable patterns and disordered patterns, respectively. For a neuronal network coupled by two single-layer networks with noise intensity differences between layers, we find that the two-layer network can achieve synchrony as the interlayer coupling strength increases. The synchronous states strongly depend on the interlayer coupling strength and the noise intensity difference between layers.     

Magnetic Phase Transitions in CePtSn

CePtSn, crystallizing in the orthorhombic TiNiSi-type structure, exhibits two antiferromagnetic transitions at T _N=7.8 K and T _M=5.2 K. Low-temperature X-ray diffraction study has been done to investigate changes in lattice parameters connected with these magnetic phase transitions. Specific-heat data in the same temperature region are also presented. Magnetization isotherms at T>T _N up to 14 T have been measured and the obtained results are compared with theoretical calculations based on a microscopic model Hamiltonian.     

Magnetoelectric effect in a magnetostrictive-piezoelectric bilayer structure

The results of theoretical and experimental investigations of the magnetoelectric effect in a magnetostrictive-piezoelectric bilayer structure have been presented. The expression for the magnetoelectric voltage coefficient in the region of electromechanical resonance has been derived based on the joint solution of the equations of motion for the magnetostrictive and piezoelectric media and the constitutive relations. The dependence of the magnitude of the effect on the thickness of the ferrite and piezoelectric layers has been analyzed. The experimental results for nickel-lead zirconate-titanate bilayer structures have been reported. The theoretical results agree perfectly with the experimental data.     

Phase Transition in CsHSO4 Ferroelastic in a Magnetic Field

JETP Letters - A magnetically induced deceleration of the initial stage of the isothermal phase transition of ferroelastic-superprotonic cesium hydrogen sulfate has been detected. The effect is...