Stoletov curve shows the dependence of the magnetic permeability  of ferromagnetics on the intensity of the applied magnetic field

Magnetic field

A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...

 H. The curve is named after physicist

Physicist

A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many branches of physics spanning all length scales: from sub-atomic particles of which all ordinary matter is made to the behavior of the material Universe as a whole...

 Aleksandr Stoletov

Aleksandr Stoletov

Aleksandr Grigorievich Stoletov was a Russian physicist, founder of electrical engineering, and professor in Moscow University. He was the brother of general Nikolai Stoletov.-Biography:...

 who analyzed in a long series of experiments the magnetic properties of iron rings in the period 1871–1872 during his stay at the Physical Laboratory of the University of Heidelberg.