Coercivity, saturation magnetisation and Size dependent properties of Nano particles

Coercivity, saturation magnetisation and Size dependent properties of Nano particles

Magnetic hysteresis
Magnetic induction field lags behinds Magnetic field intensity

Hysteresis loop
If an alternating magneric field is applied to the material it’s magnetic induction will traceout a loop called HYSTERESIS LOOP

Saturation of magnetization
Increase in applied external magnetic field (H) cannot increase the magnetization of material further

Retentivity of magnetization
Remaining magnetization when external magnetic field (H)
Co-ercivity of magnetization
Magnetization (B) =0 for negative to the external magnetic field (H)

Size dependent properties of nano particles
SIZE plays vital role on the mechanical properties
Plastic deformation of nanostructure coating strictly depends on the grain size

With decrease in grain size beyond certain limit, Hall-Petch eqn doesn’t apply
this indicates particular material will become softer
Reduction of granule size has remarkable effect on improvement of resistant against erosion in nanostructure and composite materials
Erosion behavior under low and average loading condition in nano-materials shows that , because of higher stiffness, erosion resistance of these materials is more than that of materials with large size.

Effect of size on Mechanical properties
It is differ from conventional or bulk structures
Effective elastic properties of these small-scale structural elements strongly depends on their size.
Small-scale structures are very sensitive to the micro-structural features of the material such as the GRAIN SIZE , the finite NUMBER OF GRAINS ,BOUNDARY LAYER THICKNESS , TEXTURE and DISLOCATION STRUCTURE .
Research studies have shown that when particles ‘ size reaches to the dimension of nanometer , remarkable improvement can be observed in strength of composites

In nanoscale bars and plates effective elastic properties of structural elements strongly depend on their size
It was found that a nano-whisker can have a mechanical strength approaching to the theoretical strength values
Strength increase becomes appreciable only on diameter less than 10microns


thanks

1. Concept of co- ercivity & saturation of magnetisation BY ESWARAN MURUGESAN 17PCH00 3 1

2. MagNEtic hysteresis Magnetic induction field lags behinds Magnetic field intensity 2

3. Saturation of magnetization Increase in applied external magnetic field (H) cannot increase the magnetization of material further Retentivity of magnetization Remaining magnetization when external magnetic field (H) Co- ercivity of magnetization Magnetization (B) =0 for negative to the external magnetic field (H) Hysteresis loop If an alternating magneric field is applied to the material it’s magnetic induction will traceout a loop called HYSTERESIS LOOP 3

4. WHY SPECIPICALLY FERRO MAGNETIC MATERIAL EXTREME form paramagnet - these are sponteneously magnetized 4

5. Domains of ferromaterials 5

6. 4 CONDITIONS OF HYSTERESIS Magnetic dipole prefers always LINE UP Net magetisim = 0 6

7. Energy if Domain opposite to H Energy if Domain parallal to H 4. Domain Boundaries can shift Let take a iron rod which is surrounded by sellinoid n turns wire this connected with DC Battery 7

8. 8

9. APPLYING THIS PHENOMENON ON NANO SCALE By Using nanomaterials of ferromagnetics Working in very efficient way and residual magnetism gets high life This is termed to be possible way of MANUFACTURING NANOBATTERIES,COMPUTER CHIPS…ETC 9

10. Size dependent properties of nano particles 10

11. introduction SIZE plays vital role on the mechanical properties Plastic deformation of nanostructure coating strictly depends on the grain size With decrease in grain size beyond certain limit, Hall- Petch eqn doesn’t apply this indicates particular material will become softer Reduction of granule size has remarkable effect on improvement of resistant against erosion in nanostructure and composite materials Erosion behavior under low and average loading condition in nano -materials shows that , because of higher stiffness, erosion resistance of these materials is more than that of materials with large size 11

12. Effect of size on Mechanical properties It is differ from conventional or bulk structures Effective elastic properties of these small-scale structural elements strongly depends on their size. Small-scale structures are very sensitive to the micro-structural features of the material such as the GRAIN SIZE , the finite NUMBER OF GRAINS ,BOUNDARY LAYER THICKNESS , TEXTURE and DISLOCATION STRUCTURE . Research studies have shown that when particles ‘ size reaches to the dimension of nanometer , remarkable improvement can be observed in strength of composites 12

13. In nanoscale bars and plates effective elastic properties of structural elements strongly depend on their size It was found that a nano -whisker can have a mechanical strength approaching to the theoretical strength values Strength increase becomes appreciable only on diameter less than 10microns 13

14. Hall- petch equation 14

15. Hardness , tensile , strain 15

16. 16

17. thanks 17