- the highest attainable magnetization value (magnetic moment of material volume) for particular material at given temperature.

    The value of saturation magnetization is given by M_s=m_s•p_a/P (G), where:

m_s - magnetic moment of  test specimen (the sphere 1.0 ... 1.5 mm diameter);

r_a – appearing material density;

P - mass of test specimen. Magnetic moment is measured by vibrating sample self-compensating method, at constant temperature in direct current magnetic field of 8 kOe. The relative error of  4πM_s value with probability of 0.95 is no more than ±2.5%.

 

2. Ferromagnetic resonance line ­width, DH at level - 3dB

- the difference between two magnetic field strength values at which the power absorbed by ferrite material is half the maximum absorption. The measurement of ferromagnetic resonance linewidth and effective Lande factor g_eff is executed by the resonant cavity method at 9.4 GHz on spherical specimens. The field value corresponding to maximum absorption is the resonant value (H_r) and used in calculation of  g_eff:

g_eff=2pf_o/kH_r , where:

f_o - FMR frequency (s^-1);  

k=e/2mc   (e and m  are electrical charge and mass of electron, c - velocity of light);

H_r - resonance magnetic field (Oe).

The DH measurement accuracy is +(5+2/DH)%.

 

     e = e'+je'' , tgd_e =e”/e’, where: e’ - real part of the permit­tiv­ity;  e” - imaginary part of the permittivity. Both real and imaginary parts of permittivity are determined by standard TE_10n (n is odd 3 or greater) cavity resonant method with using specimen rods (1.12 x 1.12 x 18) mm, at frequency 9.4 GHz.

where: e'- real part of the permittivity; e" – imaginary part of the permittivity;

The measurement complex dielectric permittivity is executed in accordance of the Standard International Elektrotehniсal Commission (the publication 556, 1982.). Cylindrical  TM₀₁₀ on the frequency 9,4 GHz and checking sample by size 1,12x1,12x18 mm are used.

The measurements accuracy are: e’ ≤ ±3% ; e” ≤ ±(10+ 0.06/e”)%.

 

4. Effective anisotropy field of polycrystalline materials, H_Aeff

The measurement of the anisotropy field is conducted by resonance method on sphere  within the range of frequencies 53 - 78 GHz or on Е- plates within the range of 78 - 120 GHz.

The A_eff measurement accuracy is :  ±(5+5•DH/H_Aeff)%.

 

5. Spin-wave resonance line width, DH_k

- defines dissipative properties of the materials at high microwave power. It is defined by equation:

DH_k = (4pM_s•g/2pf)h_Cmin, where:

h_Cmin - minimal microwave magnetic field amplitude at the critical power level corresponding to appearance of non-linear phenomena in ferrite (Oe);

g - giromagnetic ratio (Oe^-1•s^-1);

f - frequency of signal (Hz). The spin-wave linewidth is measured on 1...2 mm diameter sphere in a cylindrical cavity using parallel pumping tech­nique. The measurement is performed either in hollow TE_10n cavity or dielectric cavity, depending on diameter of sphere and expected  DH_k value.

The microwave signal 9.4 GHz is fed by pulse duration of 1ms, 3ms  or 5ms  with on-off time ratio q=2500.

The  measurement accuracy is +15%.

 

- characteristics of hysteresis loop of materials are measured by induction method on toroidal specimens. The test is executed in quasistationary regime of remagnetization at 209 Hz in applied field of H_m=5H_c.

The measurement accuracy of B_r, H_c, is ± 5%.