in M-H curve the Hci is the intrinsic coercivity for reducing the magnetisation to Zero, were as the coercivity Hc  is used for B-H curve for reducing the flux density to Zero.

H c can be determined from the variation between the magnetization  and the applied magnet field intensity H . The magnetization must be reach to saturation. It means irreversible region to obtain the hysterises loop. Actually it results for ferro , ferri and antiferromagnetic materials.

B- H  relation , useful to determine the permeability of the substance which is greater than that for vacuum.  The value of B represents the applied exterinal magnetic field

B=µ0(H+M) for a magnetic material. In the B-H curve the B can be increased while H increases even after the material is saturated. because the first part in the equation is going th the space but the second part will be constant. therefore the M-H curve is constant after the material is saturated. I hope the information is useful for the researchers WHO need.

distinction between B-H and M-H curve, please find the file,this gives you a better understanding.

Thankyou everyone for your useful suggestions. I hope this would help me during my research work.

In cgs system, B = H + (4pi)*M. Accordingly, wile the M-H curve saturates after a given H-field strength, the B-H curve exhibits a linear relation after saturation induction (Bs). As the H field is reduced to zero, the B-field decreases from Bs down to the retentivity (Br). Then reversing the H-field direction and increasing its strength leads to the reduction of B down to zero at a negative applied H-field called the coercivity Hc. At this field, the magnetization of the sample is still positive and is given by the absolute value of Hc divided by 4pi.  To reduce the magnetization down to zero, we need to increase the reverse H-field, and M reaches zero at a reverse field called "intrinsic coercivity". Therefore, the intrinsic coercivity (sometimes written as MHc) is usually greater than the coercivity obtained from the B-H relation. In soft magnetic materials, the difference between the two coercivities is negligible (due to the small remanance). However, in permanent magnets, the difference could be significant.

Thankyou Sami Mahmood sir ,

in my experience on soft-magnets, i use M-H loops (using VSM) to investigate saturation magnetization and the B-H loops (using BH Tracer) to investigate coercivity, permeability. accuracy of magnetic field in a M-H loop is about 8 A/m (equal to 0.1 Oe), but the accuracy of magnetic field in a B-H loop is about 0.5 A/m. So it is best to use the B-H tracer to measure the coercivity of a sot-magnet, and VSM to measure the coercivity of a hard-magnet.

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All answers are interesting & informative , Thanks all