Dear Dr. Pervaiz Ahmad ,

I suggest you to have a look at the following paper:

-Structure and Properties of Magnesium Diboride and the Effect of Additions

Tatiana PRIKHNA, Michael EISTERER, Athanasios G. MAMALIS, Artem KOZYREV, Vitaliy ROMAKA, Vladimir SOKOLOVSKY, Myroslav KARPETS, Viktor MOSHCHIL, Vladimir SVERDUN, Semyon PONOMARYOV and Tetiana SERBENYUK

Materials Science ForumOnline:2018-03-01ISSN: 1662-9752, Vol. 915, pp 65-70 (2018)

Available, on RG, at: https://www.researchgate.net/publication/322632377_Structure_and_properties_of_magnesium_diboride_effect_of_additions

Best regards, Pierluigi Traverso.

Dear Dr. Pervaiz Ahmad ,

I suggest you to have a look at the following paper:

-Structure and Properties of Magnesium Diboride and the Effect of Additions

Tatiana PRIKHNA, Michael EISTERER, Athanasios G. MAMALIS, Artem KOZYREV, Vitaliy ROMAKA, Vladimir SOKOLOVSKY, Myroslav KARPETS, Viktor MOSHCHIL, Vladimir SVERDUN, Semyon PONOMARYOV and Tetiana SERBENYUK

Materials Science ForumOnline:2018-03-01ISSN: 1662-9752, Vol. 915, pp 65-70 (2018)

Available, on RG, at: https://www.researchgate.net/publication/322632377_Structure_and_properties_of_magnesium_diboride_effect_of_additions

Best regards, Pierluigi Traverso.

MgB2 (as well as C-doped MgB2 aka. MgB2-xCx) are paramagnetic above the respective critical temperatures.

"Electron paramagnetic resonance and Raman spectroscopy studies on carbon-doped MgB2 superconductor nanomaterials" in Journal of Applied Physics 117, 153905 (2015); https://doi.org/10.1063/1.4918608

This shouldn't depend on the particle size. Below Tc MgB2 is superconductive and therefore diamagnetic.

The following link may be useful for you Mr. Ahmad https://www.researchgate.net/publication/243409446_Magnetic_Properties_and_Critical_Currents_of_MgB2