Magnetic semiconductor

About: Magnetic semiconductor is a research topic. Over the lifetime, 8746 publications have been published within this topic receiving 262880 citations.

Transport properties and origin of ferromagnetism in (Ga, Mn)As

Abstract: Magnetotransport properties of $p$-type ferromagnetic (Ga,Mn)As, a diluted magnetic semiconductor based on III-V semiconductors, are measured and the $p\ensuremath{-}d$ exchange between holes and Mn $3d$ spins is determined. The ferromagnetic transition temperatures calculated based on the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction using the exchange reproduce remarkably well the observed ferromagnetic transition temperatures, demonstrating that ferromagnetism of (Ga,Mn)As has its origin in the RKKY interaction mediated by holes.

Zinc Oxide: Fundamentals, Materials and Device Technology

Abstract: Preface 1 General Properties of ZnO 1.1 Crystal Structure 1.2 Lattice Parameters 1.3 Electronic Band Structure 1.4 Mechanical Properties 1.5 Vibrational Properties 1.6 Thermal Properties 1.7 Electrical Properties of Undoped ZnO 2 ZnO Growth 2.1 Bulk Growth 2.2 Substrates 2.3 Epitaxial Growth Techniques 3 Optical Properties 3.1 Optical Processes in Semiconductors 3.2 Optical Transitions in ZnO 3.3 Defects in ZnO 3.4 Refractive Index of ZnO and MgZnO 3.5 Stimulated Emission in ZnO 3.6 Recombination Dynamics in ZnO 3.7 Nonlinear Optical Properties 4 Doping of ZnO 4.1 n-Type Doping 4.2 p-Type Doping 5 ZnO-Based Dilute Magnetic Semiconductors 5.1 Doping with Transition Metals 5.2 General Remarks about Dilute Magnetic Semiconductors 5.3 Classification of Magnetic Materials 5.4 A Brief Theory of Magnetization 5.5 Dilute Magnetic Semiconductor Theoretical Aspects 5.6 Measurements Techniques for Identification of Ferromagnetism 5.7 Magnetic Interactions in DMS 5.8 Theoretical Studies on ZnO-Based Magnetic Semiconductors 5.9 Experimental Results on ZnO-Based Dilute Magnetic Semiconductors 6 Bandgap Engineering 6.1 MgxZn1-xO Alloy 6.2 BexZn1-xO Alloy 6.3 CdyZn1-yO Alloy 7 ZnO Nanostructures 7.1 Synthesis of ZnO Nanostructures 7.2 Applications of ZnO Nanostructures 8 Processing, Devices, and Heterostructures 8.1 A Primer to Semiconductor-Metal Contacts 8.2 Ohmic Contacts to ZnO 8.3 Schottky Contacts to ZnO 8.4 Etching of ZnO 8.5 Heterostructure Devices 8.6 Piezoelectric Devices 8.7 Sensors and Solar Cells Based on ZnO Nanostructures 8.8 Concluding Remarks

Electrical spin injection and accumulation at room temperature in an all-metal mesoscopic spin valve

Abstract: Finding a means to generate, control and use spin-polarized currents represents an important challenge for spin-based electronics, or `spintronics'. Spin currents and the associated phenomenon of spin accumulation can be realized by driving a current from a ferromagnetic electrode into a non-magnetic metal or semiconductor. This was first demonstrated over 15 years ago in a spin injection experiment on a single crystal aluminium bar at temperatures below 77 K. Recent experiments have demonstrated successful optical detection of spin injection in semiconductors, using either optical injection by circularly polarized light or electrical injection from a magnetic semiconductor. However, it has not been possible to achieve fully electrical spin injection and detection at room temperature. Here we report room-temperature electrical injection and detection of spin currents and observe spin accumulation in an all-metal lateral mesoscopic spin valve, where ferromagnetic electrodes are used to drive a spin-polarized current into crossed copper strips. We anticipate that larger signals should be obtainable by optimizing the choice of materials and device geometry.

Theory of Current-Driven Domain Wall Motion: Spin Transfer versus Momentum Transfer

Abstract: A self-contained theory of the domain wall dynamics in ferromagnets under finite electric current is presented. The current has two effects: one is momentum transfer, which is proportional to the charge current and wall resistivity (rho(w)); the other is spin transfer, proportional to spin current. For thick walls, as in metallic wires, the latter dominates and the threshold current for wall motion is determined by the hard-axis magnetic anisotropy, except for the case of very strong pinning. For thin walls, as in nanocontacts and magnetic semiconductors, the momentum-transfer effect dominates, and the threshold current is proportional to V(0)/rho(w), V0 being the pinning potential.

High temperature ferromagnetism with a giant magnetic moment in transparent co-doped SnO(2-delta).

Abstract: The occurrence of room temperature ferromagnetism is demonstrated in pulsed laser deposited thin films of Sn(1-x)Co(x)O(2-delta) (x<0.3). Interestingly, films of Sn(0.95)Co(0.05)O(2-delta) grown on R-plane sapphire not only exhibit ferromagnetism with a Curie temperature close to 650 K, but also a giant magnetic moment of 7.5+/-0.5 micro(B)/Co, not yet reported in any diluted magnetic semiconductor system. The films are semiconducting and optically highly transparent.