DC to DC converter noise issute

[avais20]

I am making a switch mode power supply 24vdc to 12vdc using
push pull topology . Transformer is center tap at both sides ground
is not isolated . Rectification is via MUR3020. Switching frequency
100khz using SG3525.
I have spikes of about 100~ 200mv on my ground line as shown
in picture attached. Spike levels increase with load current . Which
is from 0 to 10 amperes.
I am not an expert in smps and i am not a beginner either.

I want to know what is causing these spikes, and how to reduce or
completely get rid of them.

 

[Genovator]

Circuit diagram is required. Can you provide it?

 

[Tahmid]

If you're measuring noise at ground, what is your reference?

Are you measuring the noise along the ground line, whereas one point (eg battery -ve) is the reference?

 

[avais20]

Ok, I just looked at this link

**broken link removed**

and now i am between relief and further confusion!
These are exactly the wave forms that i see on my board.
Thamid, you will note that ground is the measurement point and it is also the reference.
The spikes exist exactly on the ground line as they appear on the output voltage in video.
Now relief if: This is just radiated noise pickup!
Confusion: Because i know for sure that connecting the probe like this and checking the ground line is the way to check for "Common Mode noise", which is kind of a serious noise!.
So what do you guys say now?