Patent ID: 11922986
Assignee: SHANDONG UNIVERSITY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 4:
5. The method of adjusting and controlling the exchange biases in the two directions to achieve multiple-state storage capability according to claim 4, wherein:
in the step (A), the value range of the external field Hx is −1000 Oe<Hx<−50 Oe and +50 Oe<Hx<+1000 Oe; the value range of the pulse current Ix is −20 mA<Ix<−10 mA and +10 mA<Hx<+20 mA, and the pulse current density is 106-107 A/cm2; both Hx and Ix are set along the length direction of the Hall bar;
the in-plane exchange bias and out-of-plane exchange bias are set to different arrangement modes under the combined action of an external field and pulse current to achieve non-volatile ten-state storage capability; which is as follows:
i) current pulses and an external field (external field Hx=+100 Oe; current pulses Ix=+19 mA) are applied at the same time to set the magnetic state of the in-plane ferromagnetic layer to the +x direction and the magnetic moment of the interface between the perpendicular ferromagnetic layer and the perpendicular anti-ferromagnetic layer to the +z direction, wherein the x direction is the length direction of the Hall bar and also the direction in which the current is applied; the y direction is the width direction of the Hall bar and also the direction in which the Hall voltage is tested; the z direction is the sample growth direction; and
ii). after the external field and current pulses applied in the step i) are removed, the current pulses Ix=+19 mA are applied, and the impulse strength of the write current pulses Ix is adjusted to make Ix fall between −14 mA and −19 mA; then, the out-of-plane anomalous Hall curve is measured, and a stable resistance state is obtained;
the step ii) is repeated nine times with varying pulse strength of the write-current pulses Ix each time to obtain ten stable resistance states; these ten remanence states are used to represent 0 through 9 in decimal to achieve the non-volatile ten-state storage capability.