Structure and magnetization of a magnetoactive ferrocomposite

Abstract

This work is devoted to the theoretical study of the structural and magnetic properties of an ensemble of single-domain interacting magnetic nanoparticles immobilized in a non-magnetic medium. This model is...

Effect of Polydispersity on the Structural and Magnetic Properties of a Magnetopolymer Composite

“…The method of expanding Hamiltonians into a series in terms of the Langevin susceptibility is described in detail in Ref. [ 33 ] for a monodisperse ensemble of magnetic particles. It is worth noting that if we replace , , (or , , ), then Equations ( 11 ) and ( 12 ) are exactly transformed into the expression for the magnetic moment orientation probability density of a monodisperse system derived in [ 33 ] (Equation ( 14 ) in [ 33 ]).…”

“…[ 33 ] for a monodisperse ensemble of magnetic particles. It is worth noting that if we replace , , (or , , ), then Equations ( 11 ) and ( 12 ) are exactly transformed into the expression for the magnetic moment orientation probability density of a monodisperse system derived in [ 33 ] (Equation ( 14 ) in [ 33 ]). In Equations ( 11 ) and ( 12 ), the terms of order determine the contribution of the dipole–dipole interaction to the distribution function of easy axes;the zero order terms in the Langevin susceptibility correspond to the ideal system approximation: …”

“…The expansion of the distribution function to a virial series is described in detail in Ref. [ 33 ]. In Equations ( 16 ) and ( 17 ) the terms that do not contain Langevin susceptibility determine the magnetization of an ideal BD system ; the terms describe the contribution of the dipole–dipole interaction to the magnetization of a BD ensemble of immobilized magnetic particles.…”

“…In Equations ( 16 ) and ( 17 ) the terms that do not contain Langevin susceptibility determine the magnetization of an ideal BD system ; the terms describe the contribution of the dipole–dipole interaction to the magnetization of a BD ensemble of immobilized magnetic particles. Expressions ( 16 ) and ( 17 ) are transformed into the magnetization of the monodisperse system (Equations (26) in [ 33 ]), assuming , , (or , , ).…”

“…The dependence of the MPC’s properties on the structuring features of the magnetic filler has been demonstrated in experimental works [ 9 , 16 , 17 , 18 , 19 ]. To predict the magnetic properties of an MPC, theories have been developed for various cases of the magnetic filler’s orientation texturing: the easy magnetization axes are aligned parallel to each other [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ], orientation texturing is absent [ 27 , 29 , 30 , 31 ], and the orientation of the easy magnetization axes is formed under the influence of a constant magnetic field [ 32 , 33 , 34 ]. A magnetic response theory of immobilized particles with a specific spatial arrangement of magnetic particles has been developed in [ 35 , 36 , 37 , 38 , 39 ].…”