On the theory of quantum stochastic resonance in single-domain magnetic particles

Dependence of the Dynamic Susceptibility of Superparamagnetic Particles on the Strength of a Constant Magnetic Field Perpendicular to the Direction of Particle Easy Magnetization

“…ultralow temperatures, because it determines the rate of tunnel transitions of the particle magnetic moment vector [5,6]. In this work, we consider over-the-barrier magnetic reversal, and the problem is to elucidate whether or not the constant field can control the intrinsic thermal noise intensity at a fixed temperature under conditions of stochastic resonance.…”

Stochastic Resonance in Finely Dispersed Magnets: Influence of a Constant Magnetic Field Applied along the Direction of Easy Magnetization

“…The unique features of small magnetic particles are of interest not only for applied studies. The previous studies devoted to the phenomenon of stochastic resonance of disperse uniaxial particles in the case of over-the-barrier [4,5] or subbarier mechanisms of magnetic reversal [6][7][8] have demonstrated the characteristic nonmonotonic dependence of the system response to a weak variable field on the intrinsic noise having the thermal or quantum nature. Values of the dynamic magnetic susceptibility components and signal-to-noise ratio obtained in the two-state approximation for single-domain particles in stochastic resonance were also confirmed by the results of numerical calculations based on a solution of the Fokker-Planck equation by the method of matrix continued fractions [9,10].…”

Matrix Elements of the System of Moment Equations Governing the Kinetics of Superparamagnetic Particles

“…(3) for a variety of particular problems are given, for example, in Refs. [9,[11][12][13][14][15][16][17]. The solution of Gilbert's equation (1) can also be reduced to 0031-9007͞99͞82(14)͞2967(4)$15.00 the moment system (3) by means of an appropriate transformation of the variables and by direct averaging (without recourse to the Fokker-Planck equation) of the stochastic equation so obtained (e.g., [18][19][20][21]).…”

“…Equation (14) differs from that used in other works (for example, [11][12][13][14][15][16]), where W itself was sought in the form of Eq. (15).…”

“…(15). The representation (14) has an advantage that it is unnecessary to apply additional conditions to the distribution function in order that it should be physically meaningful (e.g., W should be positive and real).…”