Eigenschaften von ferrit-speicherelementen bei sehr tiefen temperaturen

Abstract

The electrical and magnetic properties of ferrite memory cores (a Li-Ni ferrite and a usual Mg-Mn-Zn ferrite) were investigated in the temperature range between 4.2 and 400°K. Both materials show a quite different behavior at very intensive refrigeration. The remanent induction, and especially the coercivity and switching coefficient of the Mg-Mn-Zn ferrite, rise conspicuously if the temperature decreases. To the contrary, these values change relatively little at the Li-Ni ferrite. Consequently, the peak voltages and the switching time of the sense signals ( uV_{1}, dV_{2} , and t_{0s} ) of the Li ferrite deviate at 4.2°K only a little from the corresponding parameters at 300°K, if the driving current is increased by about 40 percent. Moreover, in the range from approximately 100°K down to the liquid helium temperature, and possibly below it, these ferrites have a smaller switching coefficient than the Mg-Mn-Zn ferrites.