**Property of Soft ferrite:**

** **

**1**High permeability, permeability (symbol μ) is a measure of magnetic field sensitivity.

**2**Low coercivity Hc show that magnetic material is not only vulnerable to external magnetic field magnetization but also easily affected by external magnetic field or other factors demagnetization and magnetic loss is lower.

**3**High saturation flux density Bs and high saturation magnetization Ms make it easier to obtain high magnetic permeability μ and low coercivity Hc and also can increase energy density.

**4**Low magnetic loss and dielectric loss, it requires a low coercive force Hc and a high resistivity.

**5 **High stability, it requires that the properties of soft magnetic ferrite above-mentioned have high stability to environmental factors such as temperature and vibration

**The performance parameters of soft magnetic Ferrite:**

** **

**1. Initial permeability, μi**

Where

**2. Effective permeability, μ _{e} **

This is usually defined as the permeability of a core forming a closed circuit where leakage flux is negligibly small.

Where

L: Self-inductance of core with coil (H)

N: Number of turns

Le: Effective magnetic path length (m)

^{2})

**3. Saturation flux density, Bs (T)**

**4. Remanence, Br (T)**

The value of density retained by the core when the magnetic field is reduced from the saturation magnetic flux density to zero.(Fig.1)

**5. Coercivity, Hc (A/m)**

**6. Loss factor, tanδ**

This is the sum of the hysteretic loss factor, eddy current loss factor and residual loss factor.

tanδ= tanδ_{h }+ tanδ_{e} + tanδ_{r}

Where

tanδ_{h} is the hysterias loss factor

tanδ_{e} is the eddy current loss factor

tanδ_{r} is the residual loss factor

**7. Relative loss factor, tanδ/μi**

This is the ratio of loss factor to permeability.

tanδ/μi (for materials)

tanδ/μe (for cores with gaps in the magnetic circuit)

**8. Quality factor, Q**

This is the reciprocal of the loss factor and is given by

**9. Temperature coefficient, αμ (1/K)**

Where

μ1: Permeability at temperature T1

**10. Relative temperature coefficient, αμr (1/K)**

**11. Discommendation factor, DF**

**12. Curie temperature, Tc ****（****℃****）**

**13. Electrical resistively, ****r**** (Ω.m)**

This is the electrical resistance per unit length and cross-sectional area of a magnetic core.

** **

**14. Density, d (kg/m ^{3}) **

This is the weight per unit volume of a magnetic core as expressed below.

d =W/V

Where

W: Weight of magnetic body (kg)

V: Volume of magnetic body (m^{3})

** **

**15. Power loss, Pc (kW/ m ^{ 3})**

Where

E: voltage effective value applied to coil

Bm: peak value of magnetic flux density（T）

f: Frequency (Hz)

N: Number of tunes

Ae: Effective cross-sectional arum (m^{2})

**16. Inductance factor, **

This is the inductance per turn of the coil would around the ferrite cores with definite shape and dimension.

_{L}^{2}

Where

L: Inductance of the coil with ferrite core,

N: Number of tunes