Ferromagnetic Resonance

Abstract

The following information can be accessed with the help of such resonance experiments. (i) Electrical structure of point defects by looking at the absorption in a thin structure. (ii) The line width with the movement of spin or surroundings isn't changed. (iii) The distribution of the magnetic field in solid by looking at the of the resonance line position (chemical shift and etc.). (iv) Collective spin excitations. Ferromagnetic Resonance-Theory and Applications 2 The atoms of ferromagnetic coupling originate from the spins of d-electrons. The size of μ permanent atomic dipoles create spontaneously magnetized. According to the shape of dipoles materials can be ferromagnetic, antiferromagnetic, diamagnetic, paramagnetic and etc. Ferromagnetic resonance (FMR) technique was initially applied to ferromagnetic materials, all magnetic materials and unpaired electron systems. Basically, it is analogous to the electron paramagnetic resonance (EPR). The EPR technique gives better results at unpaired electron systems. The FMR technique depends on the geometry of the sample at hand. The demagnetization field is observed where the sample geometry is active. The resonance area of the sample depends on the properties of material. The FMR technique is advantageous because it does not cause damage to materials. Also, it allows a three dimensional analysis of samples. The FMR occurs at high field values while EPR occurs at low magnetic field values. Also, line-width of ferromagnetic materials is large according to paramagnetic materials. Exchange interaction energy between unpaired electron spins that contribute to the ferromagnetism causes the line narrowing. So, ferromagnetic resonance lines appear sharper than expected. The FMR studies have been increased since the EPR was discovered in

Electric tuning of magnetization dynamics and electric field-induced negative magnetic permeability in nanoscale composite multiferroics

“…Furthermore, the linear growth of H r with E implies an increasing negative surface spin density, which will give rise to a decrease of the effective damping, and more detectable, a sign transition in small α at the critical electric field. Taking the odd-parity of the imaginary part of the magnetic susceptibly and its relation to damping α 39 , we expect a phase transition close to the frequency of FMR, which is in line with the experimental observations. The nonmonotonic behavior of the effective Δ eff may be due to a nonlinear interplay of the higher order effects with nonlocal damping 22 , originating from the dissipative flow of nonequilibrium intralayer spin currents within the interface.…”

“…For an insight into the electrical tuning of magnetic dynamics, we study the resonance spectra based on the phenomenological LLG equation, which has been widely used for interpreting and predicting vast experimental results of magnetic structures (See Ref. 39 and the supplementary ). We find…”

Paramagnetic nature of Mn doped ZnS nano particles in opto electronic device application

“…resonance is not resolved for Mn fractions above 0.5 % [24]. 5 % doped ZnS nano particles have the central sharp line at g = 2.002293, a sextet of relatively broad lines was observed at g = 2.0008 [25] and eight-line pattern in [26]. For nanoparticles, however, the ESR signal with the HF structure was resolved even for samples with 30 % Mn dopant [11].…”

Structural, Magnetic, and X-Band Microwave Absorbing Properties of Ni-Ferrites Prepared Using Oxidized Mill Scales

“…NiFe2O4 as ferrimagnetic materials are closely related with the resonance behaviour, which is strongly associated to magnetic materials. Ferromagnetic resonance, electron paramagnetic resonance, among others, are few phenomenons occur at varying frequencies [10], which compose the resonance behaviour of materials. X-band (8-12 GHz) is widely used in terrestrial wireless communication.…”