Can you imagine a laptop hard drive the size of a grain of rice? Skyrmion, a mysterious quasiparticle structure in the magnetic field, could make this seemingly unthinkable idea a reality, with more storage space and faster data transfer rates for this "grain of rice. So how to observe this strange particle structure? The CIQTEK Quantum Diamond Atomic Force Microscope (QDAFM), based on the nitrogen-vacancy (NV) center in diamond and AFM scanning imaging, can tell you the answer. What is Skyrmion With the rapid development of large-scale integrated circuits, the chip process into the nanometer scale, the quantum effect is gradually highlighted, and "Moore's Law" encountered physical limits. At the same time, with such a high density of integrated electronic components on the chip, the thermal dissipation problem has become a huge challenge. People urgently need a new technology to break through the bottleneck and promote the sustainable development of integrated circuits. Spintronics devices can achieve higher efficiency in information storage, transfer, and processing by exploiting the spin properties of electrons, which is an important way to break through the above dilemma. In recent years, topological properties in magnetic structures and their related applications are expected to be the information carriers of next-generation spintronic devices, which is one of the current research hotspots in this field. The skyrmion (hereafter referred to as a magnetic skyrmion) is a topologically protected spin structure with quasiparticle properties, and as a special kind of magnetic domain wall, its structure is a magnetization distribution with vortices. Similar to the magnetic domain wall, there is also a magnetic moment flip in the skyrmion, but unlike the domain wall, the skyrmion is a vortex structure, and its magnetic moment flip is from the center outward, and the common ones are Bloch-type skyrmions and Neel-type skyrmions. Figure 1: Schematic diagram of the structure of skyrmion. (a) Neel-type skyrmions (b) Bloch-type skyrmions The skyrmion is a natural information carrier with superior properties such as easy manipulation, easy stability, small size, and fast driving speed. Therefore, the electronic devices based on skyrmions are expected to meet the performance requirements for future devices in terms of non-volatile, high capacity, high speed, and low power consumption. What are the Applications of Skyrmions Skyrmion Racetrack Memory Racetrack memory uses magnetic nanowires as tracks and magnetic domain walls as carriers, with electric current driving the motion of the magnetic domain walls. In 2013, the researchers proposed the skyrmion racetrack memory, which is a more promising alternative. Compared to the drive current density of a magnetic domain wall, the skyrmion is 5-6 orders of magnitude smaller, which can lead to lower energy consumption and heat generation. By comp...
View MoreDid you know that light can create sound? In the late 19th century, scientist Alexander Graham Bell (considered one of the inventors of the telephone) discovered the phenomenon of materials producing sound waves after absorbing light energy, known as the photoacoustic effect. Alexander Graham Bell Image Source: Sina Technology After the 1960s, with the development of weak signal detection technology, highly sensitive microphones and piezoelectric ceramic microphones appeared. Scientists developed a new spectroscopic analysis technique based on the photoacoustic effect - photoacoustic spectroscopy, which can be used to detect substances of samples and their spectroscopic thermal properties, becoming a powerful tool for physicochemical research in inorganic and organic compounds, semiconductors, metals, polymer materials, etc. How can we make light create sound?As shown in the figure below, a light source modulated by a monochromator, or a pulsed light such as a pulsed laser, is incident on a photoacoustic cell. The material to be measured in the photoacoustic cell absorbs light energy, and the absorption rate varies with the wavelength of the incident light and the material. This is due to the different energy levels of the atomic molecules constituted in the different materials, and the absorption rate of light by the material increases when the frequency ν of the incident light is close to the energy level hν. The atomic molecules that jump to higher energy levels after absorbing light do not remain at the higher energy levels; instead, they tend to release energy and relax back to the lowest ground state, where the released energy often appears as thermal energy and causes the material to expand thermally and change in volume.When we restrict the volume of a material, for example, by packing it into a photoacoustic cell, its expansion leads to changes in pressure. After applying a periodic modulation to the intensity of the incident light, the temperature, volume, and pressure of the material also change periodically, resulting in a detectable mechanical wave. This oscillation can be detected by a sensitive microphone or piezoelectric ceramic microphone, which is what we call a photoacoustic signal. Principle Schematic How does a lock-in amplifier measure photoacoustic signals? In summary, the photoacoustic signal is generated by a much smaller pressure signal converted from very small heat (released by atomic or molecular relaxation). The detection of such extremely weak signals necessarily cannot be done without lock-in amplifiers. In photoacoustic spectroscopy, the signal collected from the microphone needs to be amplified by a preamplifier and then locked to the frequency signal we need by a lock-in amplifier. In this way, a high signal-to-noise ratio photoacoustic spectroscopy signal can be detected and the properties of the sample can be measured. CIQTEK has launc...
View MorePaleomagnetism is an interdisciplinary discipline between geology, physics, and geophysics. Paleomagnetism generally studies the direction and strength of the Earth's magnetic field, planetary launch and its evolution pattern during geological periods by measuring the natural residual magnetization intensity of rocks or ancient artifacts. Rocks are a combination of natural minerals, and their residual magnetism generally comes from ferromagnetic minerals in rocks, containing primary and secondary remanent magnetism. The so-called primary remanent magnetism refers to the geomagnetic field information recorded when the rocks were formed. In contrast, the residual magnetism obtained after the formation of rocks is called secondary remanence, such as that obtained by rocks under the action of external magnetic fields (e.g., natural lightning strikes, erosion by running water and sand). Since paleomagnetism studies the characteristics of the geomagnetic field at the time of rock formation, accurate measurement of primary remanent magnetism becomes an important research tool. Currently, rock magnetism is analyzed by measuring the net magnetic moment of large samples of millimeter to centimeter size. Common instruments for scientific analysis include superconducting petrographs and vibrating sample magnetometers. However, at the submicron scale, geological samples are usually inhomogeneous in mineralogy and texture, with only a small fraction of ferromagnetic particles carrying residual magnetization. Therefore, characterizing rock magnetism in this context requires a technique that can image magnetic fields at the nanoscale of space and with high sensitivity. For example, scanning superconductivity microscopy (SQUID), magnetoresistive microscopy, and Hall microscopy, which are being widely used, are examples. (a) Quantum diamond microscopy at Harvard University (b) Measurement of residual magnetization in geological samples In 2011, researchers demonstrated that nitrogen-vacancy chromatic cores (NV chromatic cores for short) in diamond can be used for magnetic imaging on the submicron scale.In 2017, R.L. Walsworth et al. at Harvard University used a self-built quantum diamond microscope based on NV chromatic cores to achieve imaging of rock magnetic fields with a metric spatial resolution of 5 um and a field-of-view range of 4 mm.By By reducing the distance between the diamond and the sample (≤10 um), a magnetic moment sensitivity of 10-16 A-m2 was achieved, which is comparable to and even surpasses the mainstream equipment such as SQUID, magnetoresistive microscope, and Hall microscope. In addition, the quantum diamond microscope also has the advantage of optical imaging function and fast imaging speed. It can be seen that in the detection and analysis of geological and magnetic meteorites, quantum diamond microscopy shows great potential for application, opening up a new path for wea...
View MoreThe detection and modulation of single quantum states and molecular scale imaging technology are important directions in the development of precision spectroscopy instruments. With the in-depth exploration of magnetic detection technology, CIQTEK independently produced and developed a quantum diamond single spin spectroscopy, based on the spectroscopic technology of nitrogen-vacancy system in doped diamond, which has super high magnetic detection instinct and has wide and important application prospects in different disciplines such as physics, chemistry, biology, materials, and medicine [1-11]. Development of Magnetometry Technology Figure 1: Comparison of the Indicators of Various Magnetometry Techniques Spin magnetic resonance technology is by far one of the most developed and widely used conventional techniques. Magnetic detection-related spectrometers have a long history of development, and there are different methods to achieve magnetic resonance detection which have their own advantages and disadvantages. Figure 1 visualizes the distribution of several general technical means such as Hall sensors, SQUID detectors, and the spin magnetic resonance in terms of sensitivity and resolution [12]. Compared with the conventional magnetometry techniques, the diamond-based magnetic resonance method has a large improvement in both core metrics, which provides a strong reference for the development of a quantum diamond single-spin spectroscopy. Hall sensors have been commonly used in laboratory magnetic field measurements since the 1950s. These detectors are based on the Hall effect for direct measurements of external magnetic fields [13]. When the direction of the magnetic field is different from the direction of the current in the loop, the electrons in the conductor are deflected due to the Lorentz force, and a potential difference is generated, through which the magnitude of the magnetic field is directly measured. Magnetic field probes have mainly consisted of semiconductor crystals that are able to be made into monolithic integrated circuits, which are shock resistant and easy to use but are not accurate enough. Superconducting quantum interferometer (SQUID) is a magnetic flux sensor based on Josephson junctions [14], which can measure weak magnetic signals using the variation of the voltage across the Josephson junction with the external magnetic flux in the closed loop.In the 1960s, Robert et al. successfully developed SQUID.Such magnetometry techniques have high magnetic detection sensitivity, but the instrument needs to operate in a low-temperature environment and expensive. Microscopic magnetic detection based on the diamond system is the emerging method for magnetic resonance detection. The technique combines the optical detection magnetic resonance technique (ODMR) and the point defects of nitrogen-vacancy (NV) centers in diamond, which works by preparing NV centers as quantum interferome...
View MoreIn general, the better a person's memory, the more information they can integrate and process. In quantum computing, the longer a quantum bit can "remember" a quantum state, the more calculations it can perform. The "memory" of quantum computing can be likened to coherence time. What is Coherence Time? Coherence Times is an important indicator of the quality of a quantum bit, it represents the length of time that a quantum bit can remain in a superposition state, the longer the coherence time, the more calculations a quantum computer can perform. Simply put, coherence time is also the "working time" that a quantum computer can use for computation. Currently, ion trap quantum computing has a clear advantage in realizing long coherence. What is the Difficulty of Long Coherence? Quantum bits in most quantum computing routes are highly susceptible to interference from the surrounding environment (Temperature, Noise, and even Cosmic Rays), and trying to maintain their superposition and entanglement for long periods of time is as challenging as trying to keep a group of active kittens in line. Creating the ideal quantum bit is also challenging because there are physical limitations, such as the nature of the materials and the manufacturing process that can lead to imperfect quantum bits. This is like the presence of an active cat, or even a dog, in the middle of a group of well-behaved cats, which can greatly affect the coherence time. T1 and T2, Key Technological Metrics in Quantum Computing When exploring coherence time in quantum computing, we often focus on two parameters: the T1 Time and T2 Time (T1 Time and T2 Time). They are different ways of looking at how long a quantum bit works. T1 Time determines how long you can distinguish between state 1 and state 0 of a quantum bit. When a quantum bit is excited to a high energy level (excited state), similar to a classical bit going from 0 to 1. In a classical bit, the 1 state can be maintained relatively easily, but in a quantum bit it will return to a lower energy state in a certain amount of time. This time is the energy relaxation time. During the T1 time, a quantum bit returns from a high energy state to a lower energy state, i.e., it changes from 1 back to 0. This means that the quantum bit loses the information it carries. The T2 time, on the other hand, represents the time to be able to maintain the phase information in the superposition state; if the T2 time is short, the bit superposition state may evolve into another superposition state or even cease to be a superposition state, thus losing the carried information. In short, both T1 time and T2 time are temporal parameters on the performance of a quantum bit, and they describe how long a quantum bit remains stable in terms of energy level and phase respectively. For quantum computation, longer T1 and T2 times are the goals pursued by quantum computation because it means th...
View MoreWhat is antiferromagnetic material? Figure 1: Magnetic Moment Arrangement in Antiferromagnets The common iron properties are ferromagnetism, ferroelectricity, and ferroelasticity. Materials with two or more iron properties at the same time are called multiferroic materials. Multiferroics usually have strong iron coupling properties, i.e., one iron property of the material can modulate another iron property, such as using an applied electric field to modulate the ferroelectric properties of the material and thus affect the ferromagnetic properties of the material. Such multiferroic materials are expected to be the next generation of electronic spin devices. Among them, antiferromagnetic materials have been widely studied because they exhibit good robustness to the applied magnetic field. Antiferromagnetism is a magnetic property of a material in which the magnetic moments are arranged in an antiparallel staggered order and do not exhibit a macroscopic net magnetic moment. This magnetically ordered state is called antiferromagnetism. Inside an antiferromagnetic material, the spins of adjacent valence electrons tend to be in opposite directions and no magnetic field is generated. Antiferromagnetic materials are relatively uncommon, and most of them exist only at low temperatures, such as ferrous oxide, ferromanganese alloys, nickel alloys, rare earth alloys, rare earth borides, etc. However, there are also antiferromagnetic materials at room temperature, such as BiFeO3, which is currently under hot research. Application Prospects of Antiferromagnetic Materials The knowledge of antiferromagnetism is mainly due to the development of neutron scattering technology so that we can "see" the arrangement of spins in materials and thus confirm the existence of antiferromagnetism. Maybe the Nobel Prize in physics inspired researchers to focus on antiferromagnetic materials, and the value of antiferromagnetism was gradually explored. Antiferromagnetic materials are less susceptible to ionization and magnetic field interference and have eigenfrequencies and state transition frequencies several orders of magnitude higher than typical ferromagnetic materials. Antiferromagnetic ordering in semiconductors is more readily observed than ferromagnetic ordering. These advantages make antiferromagnetic materials an attractive material for spintronics. The new generation of magnetic random access memory uses electrical methods to write and read information to ferromagnets, which may reduce the immunity of ferromagnets and is not conducive to stable data storage, and the stray fields of ferromagnetic materials can be a significant obstacle for highly integrated memories. In contrast, antiferromagnets have zero net magnetization, do not generate stray fields, and are insensitive to external fields. Therefore, antiferromagnet-based memory perfectly solves the problem of ferromagnetic memory and becomes a very attractive potential me...
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