Electronic circuit and data storage system

1. A circuit comprising a resistive element and having a first configuration in which the resistive element has a first resistance prior to exposure of at least part of the resistive element to electromagnetic radiation and a second configuration in which the resistive element has a second resistance after exposure of at least part of the resistive element to said radiation, wherein said second resistance is lower than said first resistance.

2. A circuit in accordance with claim 1 , comprising dielectric material that at least partially covers the resistive element and is at least substantially transparent to visible light and arranged to permit irradiation of said part with said electromagnetic radiation through said dielectric material.

3. A circuit comprising a resistive element and having a first configuration in which the resistive element has a first resistance-prior to exposure of at least part of the resistive element to electromagnetic radiation and a second configuration in which the resistive element has a second resistance after exposure of at least part of the resistive element to said radiation, wherein said second resistance is lower than said first resistance and further comprising a display element coupled to the resistive element, the circuit being arranged such that a state of the display element during an operation of the circuit is dependent on whether the resistive element has said first or said second resistance.

4. A circuit in accordance with claim 1 , wherein the resistive element comprises semiconductive material having a conductivity changeable by irradiation with said electromagnetic radiation.

5. A circuit in accordance with claim 4 , wherein the semiconductive material is at least substantially transparent to visible light.

6. A method of storing data, the method comprising:

receiving a piece of data to be stored;

determining a number or a dose of electromagnetic radiation according to the piece of data;

irradiating at least part of a resistive element with said number of pulses of electromagnetic radiation or said dose of electromagnetic radiation to change a resistance of the resistive element from a first resistance to a second resistance, wherein the second resistance is lower than the first resistance, and a difference between the first resistance and the second resistance is dependent on said number or said dose.

7. A data storage system comprising:

a memory comprising a resistive element;

writing means adapted to receive a piece of data, determine a dose of electromagnetic radiation or a number according to the piece of data, and irradiate at least part of said resistive element with said number of pulses of electromagnetic radiation or said dose to change a resistance of the resistive element from a first resistance to a second resistance, wherein the second resistance is lower than the first resistance, and a difference between the first resistance and the second resistance is dependent on said dose or number; and

reading means adapted to interact with said memory and being sensitive to the second resistance to ascertain said piece of data.

8. A data storage system in accordance with claim 7 , wherein the writing means comprises a radiation source, for example a laser or a lamp, arranged to emit a beam of said electromagnetic radiation.

9. A system in accordance with claim 8 , further comprising support means adapted to support the memory during said irradiation, wherein the support means is controllable to adjust at least one of a separation between the resistive element and a position of the resistive element relative to the beam.

10. A system in accordance with claim 9 , further comprising a controller arranged to control the radiation source and the support means.

11. The circuit of claim 4 wherein the resistive element comprises an indium gallium zinc oxide (IGZO) semiconductor.

12. The circuit of claim 11 wherein the resistive element further comprises an IZGO semiconductor layer having a thickness from 10 to 100 nm.