A method for preparing high-temperature superconducting diodes by multi-angle fast heavy ion superposition irradiation

Abstract

The application discloses a method for preparing a high-temperature superconducting diode by using multi-angle fast heavy ion superposition irradiation. By adjusting the ion beam incident direction, the sample is superimposed irradiated in the direction of theta 1 and theta 2 from the c-axis direction of REBCO, so that a certain angle is formed between the one-dimensional amorphization columnar defects generated along the ion incident path direction, and a pinning potential field destroying the spatial inversion symmetry is constructed. The asymmetrically distributed columnar defects can significantly change the movement resistance of the magnetic flux line in the material, so that the superconducting current faces different critical current densities (I c+ ≠I c ) in forward and reverse transport. Under the external specific magnetic field environment, the material shows obvious one-way conduction characteristics (superconducting diode effect).

Description

Technical Field

[0001] This invention belongs to the fields of heavy ion beam processing and application, superconducting material modification, and superconducting electronic devices. Specifically, it relates to a method for preparing high-temperature superconducting diodes using multi-angle fast heavy ion superposition irradiation, and more specifically, to a method for preparing REBCO high-temperature superconducting materials by introducing asymmetric columnar defects in REBCO high-temperature superconducting materials using fast heavy ion irradiation to achieve the REBCO superconducting diode effect. Background Technology

[0002] A superconducting diode is a superconducting system in which both spatial and temporal inversion symmetries are broken, and its critical current density exhibits reciprocity (i.e., Ic). c+ ≠I c When in I c+ and I c Within a defined current window, the system exhibits unimpeded transmission in one direction and resistive dissipation in the opposite direction. For superconducting quantum computers, superconducting diodes can be used to construct logic gates, memories, or detectors through unidirectional current conduction, making them the core logic element of superconducting quantum computing. Furthermore, superconducting diodes also have significant application prospects in high-efficiency rectification and lossless flux pumping.

[0003] Currently, the superconducting diode effect has been observed in various systems (such as the Josephson platform and superconducting / ferromagnetic heterojunctions), with rectification efficiencies generally ranging from 10% to 40%. However, most existing systems are based on conventional low-temperature superconductors, whose operating temperatures are far below the liquid helium temperature (4.2K), resulting in high cooling costs. Furthermore, the current-carrying capacity of these micro / nano devices is only in the microampere to milliampere range, making it difficult to meet the needs of high-power applications such as fault current limiters and wireless transmission using superconducting magnets. Therefore, developing high-temperature superconducting diodes with higher operating temperatures and stronger current-carrying capacity has significant industrial value.

[0004] REBa2Cu3O 7-x REBCO (Reverse-Boiled Coaxial) high-temperature superconducting materials possess high transition temperatures and high current-carrying capacity, making them ideal materials for fabricating high-temperature superconducting diodes. However, due to the macroscopic structural symmetry of traditional REBCO tapes (such as multilayer films deposited via PLD), their inherent spatial inversion symmetry prevents them from exhibiting diode behavior. To achieve the diode effect, it is necessary to artificially construct asymmetric structures (such as heterojunctions, corner junctions, flux vortex manipulation, or coupling with normal / ferromagnetic materials) to simultaneously break both time-reversal and spatial inversion symmetries. In 2023, Matsui H et al. irradiated YBCO with 75 MeV Au ions at a tilt of 30 degrees, but its diode efficiency at 77 K was only 1.5% (Matsui H, et al., Appl. Phys. Lett. 122,172601 (2023)).

[0005] Chinese patent ZL202411231147.1 discloses a method for improving the non-destructive current-carrying capacity of REBCO high-temperature superconducting materials and the processed REBCO high-temperature superconducting material. It discloses a method that uses fast heavy ion irradiation to introduce symmetrically distributed intersecting columnar defects along the c-axis of the superconducting tape, thereby effectively suppressing vortex creep in commercial YBCO tapes and further increasing the critical current density of the material under a magnetic field. Although the above technology is effective in improving current-carrying capacity, it has the following limitations in achieving the superconducting diode effect: 1. The symmetrically distributed intersecting columnar defects cannot break the spatial inversion symmetry, therefore, the non-reciprocity of the critical current density cannot be generated, i.e., the superconducting diode effect cannot be achieved; 2. This prior art only focuses on the current-carrying capacity of YBCO high-temperature superconducting materials as conductors and does not involve the field of fabricating superconducting devices by breaking spatial symmetry. Summary of the Invention

[0006] To overcome the challenges of extremely low operating temperature and weak current carrying capacity in existing superconducting diodes, this invention provides a method for fabricating REBCO high-temperature superconducting diodes using multi-angle superimposed fast heavy ion irradiation. This invention employs a fast heavy ion beam with an energy loss exceeding 20 keV / nm and utilizes multi-angle superimposed irradiation to generate a defect structure with broken spatial symmetry, thereby achieving non-reciprocal current control in REBCO and producing a REBCO high-temperature superconducting diode.

[0007] This invention provides a method for preparing REBCO high-temperature superconducting diodes using multi-angle fast heavy-ion superposition irradiation. This method achieves the superconducting diode effect by breaking the spatial symmetry of the magnetic flux pinning potential field within the material through stepwise irradiation at different incident angles on the same side of the c-axis of the REBCO.

[0008] Wherein, the c-axis is the crystal axis perpendicular to the CuO2 plane (i.e., the ab plane) in the REBCO orthorhombic superconducting crystal structure; In this invention, to generate amorphous columnar defects, the ion energy loss value used in the irradiation exceeds 20 keV / nm.

[0009] The total irradiation dose was controlled at 1×10 10 ~5×10 11ions / cm 2 between.

[0010] Specifically, the method includes the following steps: 1) Using the SRIM Monte Carlo dynamics simulation software, fast heavy ions with an electron energy loss value >20keV / nm were selected in the REBCO superconducting layer, and the ion range was ensured to exceed the thickness of the superconducting layer. 2) The REBCO high-temperature superconducting material is adhered to the sample holder in the target chamber and transferred to the vacuum target chamber, where the vacuum level is better than 10. -4 Pa; 3) Adjust the sample holder so that the ion beam makes an angle θ1 with the c-axis of REBCO, open the Faraday cup, and carry out the first stage of irradiation. Monitor the flux through the real-time flux detection system, and stop irradiation when the flux reaches the predetermined value F1. 4) Keep the sample holder rotation direction unchanged, so that the ion beam forms an angle θ2 with the c-axis. Open the Faraday cup again for a second irradiation. When the fluence reaches the set value F2, stop the irradiation. Among them 1×10 10 ions / cm 2 ≤F1+F2≤5×10 11 ions / cm 2 .

[0011] In step 1) of the above method, the fast heavy ion can specifically be a Ta ion, and more specifically, a Ta ion with an energy of 2.5 GeV; In step 2) of the above method, the thickness of the REBCO superconducting layer of the REBCO high-temperature superconducting material can be between 200 nm and 5 μm; In steps 3) and 4) of the above method, the angles of θ1 and θ2 can be between 0 and 90°, and θ1 ≠ θ2; different angles can also be superimposed multiple times, that is, step 4) is repeated multiple times, and the ion beam and the c-axis present at least two different angles during each irradiation. In steps 3) and 4) of the above method, F1 and F2 can be equal or unequal.

[0012] The above method further includes the following operations: after irradiation, the critical current density of the sample under forward and reverse current is measured using a cryogenic electrical transport system under a specific magnetic field to verify the window value of the superconducting diode effect and the rectification efficiency.

[0013] The REBCO high-temperature superconducting diode prepared by the above method is also within the scope of protection of this invention.

[0014] The superconducting diode can operate at liquid nitrogen temperature and has a current carrying capacity in the hundreds of amperes range, making it suitable for high-voltage applications.

[0015] Fast heavy ion irradiation, as a precision defect engineering technique, employs a fast heavy ion beam with an electron energy loss exceeding 20 keV / nm, utilizing the penetrating one-dimensional amorphous columnar defects generated in the REBCO superconducting layer as magnetic flux pinning centers. By adjusting the ion beam incident direction, the sample is superimposed with irradiation along the c-axis of the REBCO at two directions, θ1 and θ2, creating a certain angle between the one-dimensional amorphous columnar defects generated along the ion incident path, thus constructing a pinning potential field that disrupts spatial inversion symmetry. This asymmetric distribution of columnar defects significantly alters the resistance to magnetic flux lines in the material, causing the superconducting current to face different critical current densities (If) during forward and reverse transport. c+ ≠I c Under specific external magnetic field conditions, this material exhibits significant unidirectional conductivity (superconducting diode effect).

[0016] This invention makes substantial innovations based on existing technology: by improving columnar defects that are symmetric about the c-axis to columnar defects that are asymmetric about the c-axis, the spatial inversion symmetry is broken, realizing a leap from simply "enhancing the non-destructive current carrying capacity of superconducting tapes" to "fabrication of functional superconducting electronic devices (diodes)," and further expanding the application of fast heavy ion irradiation in the field of superconducting electronic devices. Attached Figure Description

[0017] Figure 1 The image shows a TEM image of Ta ions with an energy of 2.5 GeV after being irradiated at 15°+25° in YBCO superconducting material. It can be seen that asymmetric columnar defects are formed in the superconducting layer.

[0018] Figure 2(a)-(h) shows the forward and reverse IV curves of a 4mm wide REBCO superconducting tape after 25°+15° asymmetric irradiation at 77 K under different magnetic fields. As can be seen from the figure, after asymmetric irradiation, an asymmetric phenomenon occurs between forward and reverse transport. (i) represents the superconducting diode's transport efficiency η = (Ii - Ii)i. c+ -|I c- |) / (I c+ +|I c- |)×100%, when the magnetic field is ~0.13 T, η can reach 3% at 77K, and the superconducting diode effect transmission window value is 143.83 A~153.03 A.

[0019] Figure 3In Embodiment 2 of the present invention, the forward and reverse transmission asymmetry of REBCO superconducting tape after 35°+5° asymmetric irradiation is observed at 77 K. When the magnetic field is 0.25 T, the efficiency of the superconducting diode reaches its maximum, approximately 2.3%. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0021] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0022] This invention provides a method for fabricating asymmetric columnar defects in REBCO high-temperature metamaterials using multi-angle fast heavy ion beam superposition irradiation to generate a superconducting diode effect. Because it is simple and controllable, and the fabricated superconducting diode can operate at liquid nitrogen temperatures with a current carrying capacity in the hundreds of amperes, it can be used in high-power applications.

[0023] Example 1 1. YBCO tape prepared by pulsed laser deposition (on a Hastelloy substrate, a textured buffer layer and a seed layer were prepared by ion beam-assisted deposition, followed by epitaxial growth of a YBCO superconducting layer with a thickness of about 3 micrometers by ultrafast pulsed laser deposition, and a silver protective layer with a thickness of about 2 micrometers was coated on its surface by magnetron sputtering), the tape is 5 cm long and 4 mm wide; 2. Attach the superconducting tape to the sample holder and install it into the target chamber. Wait until the vacuum level inside the target chamber is less than 10... -4 After Pa, rotate the sample holder 15° clockwise; 3. The superconducting tape was irradiated with Ta ions at an energy of 2.5 GeV (the electron energy loss in the superconducting material is 34.5 keV / nm), and the irradiation flux was 2.5 × 10⁻⁶. 10 ions / cm 2 ; 4. Rotate the sample 10° clockwise and irradiate it a second time, with the irradiation dose remaining at 2.5 × 10⁻⁶. 10 ions / cm 2 ; 5. The forward and reverse current transport characteristics of the irradiated REBCO superconducting tape were characterized using an electrical measurement system cooled by liquid nitrogen, confirming the superconducting diode phenomenon.

[0024] Figure 1 The image shows a TEM image of Ta ions with an energy of 2.5 GeV after being irradiated at 15°+25° in YBCO superconducting material. It can be seen that asymmetric columnar defects are formed in the superconducting layer.

[0025] Figure 2(a)-(h) shows the forward and reverse IV curves of a 4mm wide REBCO superconducting tape after 25°+15° asymmetric irradiation at 77 K under different magnetic fields. As can be seen from the figure, after asymmetric irradiation, an asymmetric phenomenon occurs between forward and reverse transport. (i) represents the superconducting diode's transport efficiency η = (Ii - Ii)i. c+ -|I c- |) / (I c+ +|I c- |)×100%, when the magnetic field is ~0.13 T, η can reach 3% at 77K, and the superconducting diode effect transmission window value is 143.83 A~153.03 A.

[0026] Example 2 The procedure is the same as in Example 1, except that the superconducting tape is first irradiated with Ta ions at an energy of 2.5 GeV (the electron energy loss in the superconducting material is 34.5 keV / nm) by rotating it 5° clockwise. The irradiation flux is 2.5 × 10⁻⁶. 10 ions / cm 2 The sample was then rotated 30° clockwise for a second irradiation, with the irradiation dose remaining at 2.5 × 10⁻⁶. 10 ions / cm 2 .

[0027] Figure 3 The image shows the forward and reverse propagation asymmetry of a 4mm wide REBCO superconducting tape after 35°+5° asymmetric irradiation at 77 K. The superconducting diode efficiency reaches its maximum of approximately 2.3% when the magnetic field is 0.25 T.

[0028] The beneficial effects of this invention are mainly reflected in the following aspects: 1. Superconducting rectification characteristics were achieved under high temperature and high current conditions. Compared to most current low-temperature superconducting diodes that operate at extremely low temperatures (<4.2 K) and have current-carrying capacities in the milliampere range, the REBCO superconducting diode fabricated using fast heavy-ion irradiation in this invention fully leverages the intrinsic advantages of high-temperature superconducting materials. Its operating temperature can be raised to the liquid nitrogen temperature range (77 K), and it possesses a high current-carrying capacity in the hundreds of amperes range. This significant advancement enables superconducting diodes to expand from micro / nanoelectronic devices to industrial-grade high-power applications such as high-power rectification and wireless power supply using superconducting strong magnetic fields.

[0029] 2. Precise and controllable efficiency of superconducting diodes has been achieved. This invention fully utilizes the highly controllable angle of fast heavy ion irradiation. The method described in this invention is not only suitable for the precision fabrication of micro-devices in the laboratory, but also for the fabrication of larger-scale superconducting rectifiers. By flexibly adjusting the irradiation process parameters (flux, angle, etc.), the difference between the forward and reverse critical currents can be further quantitatively controlled, thereby optimizing the efficiency of the superconducting diode.

[0030] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A method for preparing REBCO high-temperature superconducting diodes using multi-angle fast heavy ion superposition irradiation, comprising: stepwise irradiation at different incident angles on the same side of the c-axis of REBCO to break the spatial symmetry of the magnetic flux pinning potential field inside the material and realize the superconducting diode effect.

2. The method according to claim 1, characterized in that, The ion energy loss value used for irradiation exceeds 20 keV / nm; and / or The total irradiation dose was controlled at 1×10 10 ~5×10 11 ions / cm 2 between.

3. The method according to claim 1 or 2, characterized in that, The method includes the following steps: 1) Using the SRIM Monte Carlo dynamics simulation software, fast heavy ions with an electron energy loss value >20keV / nm in the REBCO superconducting layer were selected, and the ion range was ensured to exceed the thickness of the superconducting layer. 2) The REBCO high-temperature superconducting material is adhered to the sample holder in the target chamber and transferred to the vacuum target chamber, where the vacuum level is better than 10. -4 Pa; 3) Adjust the sample holder so that the ion beam makes an angle θ1 with the c-axis of REBCO, open the Faraday cup, and carry out the first stage of irradiation. Monitor the flux through the real-time flux detection system, and stop irradiation when the flux reaches the predetermined value F1. 4) Keep the sample holder rotation direction unchanged, so that the ion beam forms an angle θ2 with the c-axis. Open the Faraday cup again for a second irradiation. When the fluence reaches the set value F2, stop the irradiation. Among them 1×10 10 ions / cm 2 ≤F1+F2≤5×10 11 ions / cm 2 .

4. The method according to claim 3, characterized in that, In step 1), the fast heavy ion is a Ta ion.

5. The method according to claim 3, characterized in that, In step 2), the thickness of the REBCO superconducting layer of the REBCO high-temperature superconducting material is between 200 nm and 5 μm.

6. The method according to claim 3, characterized in that, In steps 3) and 4), the angles of θ1 and θ2 are between 0 and 90°, and θ1 ≠ θ2; or different angles are superimposed multiple times, that is, step 4) is repeated multiple times, and the ion beam and the c-axis present at least two different angles during each irradiation.

7. The method according to claim 3, characterized in that, In steps 3) and 4), F1 and F2 may be equal or unequal.

8. A REBCO high-temperature superconducting diode prepared by any one of claims 1-7.

9. The REBCO high-temperature superconducting diode according to claim 8, characterized in that, The superconducting diode operates at liquid nitrogen temperature and has a current carrying capacity in the hundreds of amperes range.

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