CN110726960B

CN110726960B - Superconductive-topological semi-metal composite magnetic detector

Info

Publication number: CN110726960B
Application number: CN201911014719.XA
Authority: CN
Inventors: 伍岳; 肖立业
Original assignee: Institute of Electrical Engineering of CAS
Current assignee: Institute of Electrical Engineering of CAS
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2021-08-27
Anticipated expiration: 2039-10-24
Also published as: CN110726960A

Abstract

A superconducting-topological semimetal composite magnetic detector relates to a superconducting magnetic detector, and comprises a superconducting layer (1) and a topological semimetal layer (2). The superconducting layer (1) is of a closed superconducting loop structure, and a current compression region is adopted in one section of the superconducting loop. The topological semi-metal layer is of a sawtooth-shaped strip structure. The topological half metal layer (2) is positioned on the inner side of a current compression region in a closed loop of the superconducting layer (1), and the distance between the topological half metal layer (2) and the current compression region in the superconducting layer (1) is smaller than the width of the current compression region in the superconducting layer (1).

Description

Superconductive-topological semi-metal composite magnetic detector

Technical Field

The present invention relates to a superconducting magnetic detector.

Background

The high-sensitivity magnetometer plays an important role in the fields of scientific research, national defense and military industry, industrial production, medical treatment and the like. At present, a superconducting quantum interference device (SQUID device) is a main detection device for detecting an ultra-low magnetic field of fT magnitude. At present, the magnetic field detection precision of the SQUID device can reach below 10 fT. However, the SQUID device has the defects that the josephson junction in the device is difficult to prepare, the yield is low, the magnetic field linear response interval of the device is small, auxiliary electronic equipment such as magnetic flux lock and the like needs to be added, and the like, so that the large-scale application of the SQUID device is limited. In recent years, french scientists have prepared superconducting-Giant Magnetoresistance (GMR) magnetic sensors with magnetic field detection accuracy reaching the order of 10fT by using superconducting materials as magnetic flux-magnetic field amplification devices to replace traditional high permeability materials and combining with GMR. The device has the advantages of small volume, small noise, simple structure and high detection precision. However, such devices also suffer from the following disadvantages: first, GMR is a multilayer film structure in which a ferromagnetic pinned layer is included that is susceptible to temperature; secondly, the superconducting-giant magnetoresistance magnetic sensor needs to prepare a giant magnetoresistance-superconducting composite multilayer film structure, which also increases the preparation difficulty of the devices.

Disclosure of Invention

The invention aims to overcome the defects that a Josephson junction of the existing superconducting quantum interference device (SQUID device) is difficult to prepare, a magnetic field linear response interval is small, auxiliary electronic equipment such as magnetic flux lock and the like needs to be added, the defects that a giant magnetoresistance-superconducting composite multilayer film structure of a superconducting-giant magnetoresistance magnetic sensor is difficult to prepare, a hysteresis effect easily occurs in a GMR multilayer film structure and the like, and provides a novel superconducting-topological semimetal composite magnetic detector. The superconducting-topological semi-metal composite magnetic detector provided by the invention can solve the technical problems of low Josephson junction yield, complex giant magnetoresistance-superconducting composite multilayer film structure preparation process, small linear response interval in performance, easy occurrence of hysteresis at low temperature and the like of a superconducting weak magnetic detector comprising a SQUID device and a superconducting-giant magnetoresistance magnetic sensor.

The superconducting-topological semimetal composite magnetic detector comprises a superconducting layer and a topological semimetal layer. The superconducting layer is a closed superconducting loop, a section of current compression region exists in the superconducting loop, the width of the loop of the current compression region is smaller than that of the rest part of the superconducting loop, and the current compression region is a narrow region. The topological half metal layer is of a zigzag strip structure, the topological half metal layer is located on the inner side of a current compression region in the superconducting layer, the distance between the topological half metal layer and the current compression region in the superconducting layer is smaller than the width of the current compression region in the superconducting layer, and the length of the topological half metal layer is smaller than the length of the current compression region in the superconducting layer.

The superconducting layer is used for inducing an external magnetic field and generating superconducting shielding current in a closed loop; when the superconducting shielding current flows through the current compression region, the superconducting shielding current density increases and an enhanced induced magnetic field is generated in the vicinity of the current compression region. According to the relation that the resistance of the topological semi-metal material changes along with the magnetic field monotonously, the voltage at two ends of the topological semi-metal layer is measured through an external test circuit, the strength of the induced magnetic field which is generated and enhanced near a current compression area can be calculated, and the strength of an external magnetic field can be further calculated.

The topological half-metal layer is made of hafnium pentatelluride or lanthanum antimonide or tungsten phosphide or niobium phosphide; the superconducting layer is made of yttrium barium copper oxide.

The superconducting layer and the topological semi-metal layer are prepared by magnetron sputtering or chemical vapor deposition or a molecular beam epitaxial film growth process.

Compared with the prior art, the invention has the following advantages:

1. the superconducting device only comprises the superconducting layer and the topological half-metal layer, and the superconducting layer and the topological half-metal layer are respectively simple graphs and do not have complex structures, so that the defect that the preparation of the Josephson junction of the SQUID device is difficult is overcome.

2. The superconducting layer and the topological half-metal layer are positioned at different positions of the same plane and are not overlapped, so that the difficulty that a giant magnetoresistance-superconducting composite multilayer film structure of a superconducting-giant magnetoresistance magnetic sensor is difficult to prepare is overcome.

3. The working interval of the resistance of the topological half-metal layer which changes along with the magnetic field monotonously can reach more than 1T and is far larger than the SQUID device and the superconducting-giant magnetoresistance magnetic sensor, so that the defects that the SQUID device has a small magnetic field linearity response interval and auxiliary electronic equipment such as magnetic flux locking and the like needs to be added are overcome.

4. The invention does not comprise a ferromagnetic pinning layer, and has no hysteresis effect, thereby overcoming the defects that the GMR multilayer film structure of the superconducting-giant magnetoresistance magnetic sensor is easy to have hysteresis effect and the like.

In addition, the sensitivity of the magnetic field of the topological semi-metal material at low temperature can reach 1%/Oe, which is higher than the sensitivity of GMR, so the detection precision of the superconducting-topological semi-metal composite magnetic detector provided by the invention can reach or even exceed SQUID (superconducting-giant magnetoresistance) devices and superconducting-giant magnetoresistance magnetic sensors.

Drawings

FIG. 1 is a top view of a superconducting-topological semi-metal composite magnetic detector of the present invention; wherein 1 superconducting layer, 2 topological half-metal layer.

Detailed Description

The invention is further described with reference to the following figures and detailed description.

As shown in fig. 1, the superconducting-topological semi-metal composite magnetic detector according to the embodiment of the present invention includes a superconducting layer 1 and a topological semi-metal layer 2, the superconducting layer 1 is a closed loop structure, a current compression region exists in the superconducting loop, and the loop width of the current compression region is smaller than the width of the rest of the superconducting loop, and is a narrow region. The topological half metal layer 2 is of a zigzag strip structure, the topological half metal layer 2 is located on the inner side of a current compression region in the superconducting layer 1, the distance between the topological half metal layer 2 and the current compression region in the superconducting layer 1 is smaller than the width of the current compression region in the superconducting layer 1, and the length of the topological half metal layer 2 is smaller than the length of the current compression region in the superconducting layer 1.

As shown in fig. 1, the superconducting layer 1 is used to induce an external magnetic field, and when the external magnetic field passes perpendicularly through the closed loop of the superconducting layer 1, an induced shielding current is generated in the closed loop of the superconducting layer 1 due to the perfect diamagnetic effect of the superconducting material; when the superconducting shielding current flows through the current compression region, the density of the superconducting shielding current is increased, and an enhanced induction magnetic field is generated near the current compression region; for the topological half-metal material, at low temperature, namely below the transition temperature of the superconducting layer 1, when a magnetic field vertically penetrates through the topological half-metal material, the resistance of the topological half-metal material changes, and in a large magnetic field range, the resistance of the topological half-metal material and the magnetic field penetrating through the topological half-metal material have a monotone linear change relationship, the voltage at two ends of the topological half-metal layer is measured through an external test circuit, so that the induced magnetic field strength near the current compression area of the superconducting layer 1 can be calculated, and the strength of an external magnetic field can be further calculated.

As shown in FIG. 1, the topological half-metal layer 2 can be made of hafnium pentatelluride or lanthanum antimonide or tungsten phosphide or niobium phosphide; superconducting layer 1 may be made of yttrium barium copper oxide.

As shown in fig. 1, the superconducting layer 1 and the topological half-metal layer 2 can be prepared by magnetron sputtering or chemical vapor deposition or molecular beam epitaxy film growth process.

Claims

1. A superconductive-topological semi-metal composite magnetic detector is characterized in that: the superconducting-topological semimetal composite magnetic detector comprises a superconducting layer (1) and a topological semimetal layer (2); the superconducting layer (1) is a closed superconducting loop structure, a section of current compression region is arranged in the superconducting loop, the loop width of the current compression region is smaller than that of the rest part of the superconducting loop, and the current compression region is a narrow region; the topological semi-metal layer (2) is of a sawtooth-shaped strip structure; the topological half metal layer (2) is positioned on the inner side of a current compression region in the superconducting layer (1), the distance between the topological half metal layer (2) and the current compression region in the superconducting layer (1) is smaller than the width of the current compression region in the superconducting layer (1), and the length of the topological half metal layer (2) is smaller than the length of the current compression region in the superconducting layer (1).

2. The superconducting-topological semi-metal composite magnetic detector of claim 1, wherein: the superconducting layer (1) is used for inducing an external magnetic field and generating superconducting shielding current in a closed loop; when the superconducting shielding current flows through the current compression area, the density of the superconducting shielding current is increased, an enhanced induction magnetic field is generated near the current compression area, the voltage at two ends of the topological semi-metal layer (2) is measured through an external test circuit according to the relation that the resistance of the topological semi-metal material changes along with the monotonous change of the magnetic field, and the intensity of the enhanced induction magnetic field generated near the current compression area and the intensity of an external magnetic field are calculated.

3. The superconducting-topological semi-metal composite magnetic detector of claim 1, wherein: the topological half-metal layer (2) is made of hafnium pentatelluride or lanthanum antimonide or tungsten phosphide or niobium phosphide; the superconducting layer (1) is made of yttrium barium copper oxide; the superconducting layer (1) and the topological semi-metal layer (2) are prepared by magnetron sputtering or chemical vapor deposition or molecular beam epitaxy film growth.