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Spin Nanoscale Electronic Devices and Their Applications
Published in Khurshed Ahmad Shah, Farooq Ahmad Khanday, Nanoscale Electronic Devices and Their Applications, 2020
Khurshed Ahmad Shah, Farooq Ahmad Khanday
Spintronics has emerged as one of the most researched and emerging fields over the past two to four decades. The main aim of the field of spintronics is that the spin polarization is harnessed for the information processing and storage devices. In conventional electronics, the charge of electrons is used for the process and flow of information, which has various disadvantages, i.e., mainly power consumption and speed degradation. It has been observed that while processing the spin polarization of electrons, the power required to flip the spin of an electron is very less as compared to the actual movement of electron from one place to another. This increases the capability of reducing power consumption as well as the speed. Based on this fact, as discussed earlier as well, various spintronic devices have been reported in the open literature wherein the spin polarization is exploited in place of the charge. The devices which are being reported in the literature are not fully spintronic devices because in addition to the flipping of the spin for changing its state, the actual movement of electrons is also considered and hence they are named as hybrid spintronic devices or simply the spintronic devices. The most important spintronic devices include MTJ (which was discussed in earlier sections) and Datta–Das transistor.
Technical and analytical note on t he performance maximization of spin lasers by optimizing the spin polarization
Published in Gin Jose, Mário Ferreira, Advances in Optoelectronic Technology and Industry Development, 2019
Ritu Walia, Kamal Nain Chopra*
Spin polarization is defined as the degree to which the spin, i.e., the intrinsic angular momentum of elementary particles, is aligned in a given direction. This property is related to the spin, and therefore, to the magnetic moment of conduction electrons in ferromagnetic metals, like iron, resulting in spin-polarized currents. It is classified as static spin waves, or as preferential correlation of spin orientation with ordered lattices, which is the case in semiconductors or insulators.
Experimental Dosimetry
Published in Ben Greenebaum, Frank Barnes, Bioengineering and Biophysical Aspects of Electromagnetic Fields, 2018
In the introductory chapter, EFs and magnetic fields are discussed in detail. Briefly, an EF is a vector-force field used to represent the forces between electric charges. If the distribution of electric charges changes with time, then EF will also change. A magnetic field is proportional to the electric currents and spin polarization in magnetic materials. If the current path or the permanent magnet moves or the current magnitude changes with time, the magnetic field will also change with time. A time-varying EF creates a magnetic field and a time-varying magnetic field creates an EF [25].
Strongly correlated oxides for energy harvesting
Published in Science and Technology of Advanced Materials, 2018
Jobu Matsuno, Jun Fujioka, Tetsuji Okuda, Kazunori Ueno, Takashi Mizokawa, Takuro Katsufuji
SOC is a relativistic effect and relates the spin moment of an electron to its orbital momentum via a momentum-dependent effective magnetic field. In the presence of SOC, a charge current without any spin polarization can be converted into a pure spin current (the flow of spin angular momentum) and vice versa, known as the direct spin Hall effect and the inverse spin Hall effect (ISHE) [54–57]. Spin current-based electronics with low-energy consumption has since been discussed, where spin-current injection and detection, using charge/spin conversion by direct spin Hall effect and ISHE, played a key role. Spin Seebeck thermoelectric device is one of the promising applications; the spin current generated in a magnetic layer by temperature gradient is injected into an attached nonmagnetic layer, where the spin current is converted into the voltage with the help of ISHE. Materials with higher charge/spin conversion efficiency are required there. A variety of materials have subsequently been explored and heavy transition metals such as Pt [58] and Au [59] were found to exhibit a particularly large spin Hall angle (the maximum yield of the charge/spin conversion), 0.01–0.1 at room temperature, owing to their pronounced SOC effects.
Investigation of half-metallic and magnetic phase transition in Co2TiZ (Z = Al, Ga, In) Heusler alloys
Published in Phase Transitions, 2019
A. Amudhavalli, R. Rajeswarapalanichamy, K. Iyakutti
In conclusion, it is observed that Co2TiZ (Z = Al, Ga, and In) Heusler alloys prefer L21 phase. Co2TiZ alloys exhibit half-metallic ferromagnetism with small spin-flip gap at the minority spin state and these Heusler alloys show 100% spin polarization. The optical parameters of Co-based full Heusler alloys have been calculated. As the pressure is increased, half-metallic to metallic and ferromagnetic to non-magnetic phase transitions are observed. The positive frequency values at high symmetry points indicate that Co2TiAl, Co2TiGa and Co2TiIn are dynamically stable. Due to the specific electronic properties of Co2TiZ, these materials are very promising candidates for applications in novel spintronic devices.
Investigation of phase transition in electronic structure and magnetic properties of Fe2-x Co x TiSn Heusler alloys
Published in Phase Transitions, 2020
A. Amudhavalli, R. Rajeswarapalanichamy
The effectiveness of magneto electronic devices depends on the extent to which a current is spin-polarized [42]. The knowledge of degree of spin polarization gives an opportunity to distinguish between an ordinary ferromagnetic material with 100% spin polarization. For both scientific and technological reasons, it is important to be able to directly and easily measure degree of spin polarization of a ferromagnet. The most natural definition of degree of spin polarization at the Fermi level of a ferromagnet is [11]where is the density of electronic states at the Fermi level with corresponding spin direction (). By Equation (11), it is seen that Fe1.5Co0.5TiSn, Fe1.0Co1.0TiSn, Fe0.5Co1.5TiSn and Co2TiSn alloys are 100% spin polarized at Fermi level which elucidates the true half-metallic behaviour. Thus, these alloys can be used as spin injection devices. The net and individual magnetic moments for Fe2-xCoxTiSn (x = 0, 0.5, 1, 1.5, 2) compounds for L21 and XA phases are listed in Tables 3 and 4. Slater-Pauling rule [11,12] is proved to be a direct effect between the total magnetic moment M and the total number of valence electrons Zt when examining the half-metallic properties.where ZT is the total number of valence electrons in the unit cell.