Setting a material texture and saving it

So I am creating materials in code and trying to save them but for some reason when I save a material the texture ALWAYS reverts to "none"

How can I save the material WITH it's texture or even possibly set it after I save the new mat ?

Here is my code

         Material newMaterial = new Material(Shader.Find("Diffuse"));
 
         string matPath = "Assets/Resources/Atlas/" + textureName + "/" + textureName + ".mat";
 
         AssetDatabase.CreateAsset(newMaterial, matPath);
         newMaterial = (Material)AssetDatabase.LoadAssetAtPath(matPath, typeof(Material));
 
         newMaterial.SetTexture(textureName, texture);
 
         AssetDatabase.SaveAssets();
 
     #endregion

The bit where I set the texture seems to do nothing as my newly saved material has no texture set ?