Magnetic medium for storing information

A magnetic medium for storing information, comprising:

• at least two materials A and B connected with one another;
• said material A being a hard magnetic material, said material Λ having a first coercivity Hc and a first remenence at a given temperature when independently situated;
• said material B being a material which exhibits metamagnetic behavior in a magnetic field at said given temperature, the metamagnetic behavior of the material B being such that, even after passing repeatedly through an external magnetic field from 0 to 10 Tesla at least at a magnetic field strength below 3 Tesla, an increase in magnetization occurs as a function of the magnetic field, the increase being superproportional and having a positive curvature and occurring at a transition field Ho which is less than Hc at said given temperature;
• said increase in magnetization of said material B at said transition field level Ho being sufficient to produce domain walls in said material B to function as nucleation cells in said material A at said given temperature so as to reduce a switching field of material A to about said transition field Ho so as to permit writing to material A at said given temperature while said writing remains stable at said given temperature.