Search for dissertations about: "Johan Åkerman"

Showing result 6 - 10 of 14 swedish dissertations containing the words Johan Åkerman.

2. 6. Engineering Magnetic Droplets in Nanocontact Spin-Torque Nano-Oscillators

   Author : Sheng Jiang; Johan Åkerman; Dario Arena; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Magnetic Droplet; Magnetic Tunnel Junction; Perpendicular Magnetic Anisotropy; Spin-torque Nano-Oscillators; Spin-Valve.; Physics; Fysik;

   Abstract : Spin-torque nano-oscillators (STNOs) are nanoscale spintronic devices capable of generating highly tunable broadband microwave signals. In this thesis, I study nanocontact (NC)-based STNOs using strong perpendicular magnetic anisotropy(PMA) free layers, where a novel magnetic soliton—a magnetic droplet—exists. READ MORE

4. 7. Magnetodynamics in Spin Valves and Magnetic Tunnel Junctions with Perpendicular and Tilted Anisotropies

   Author : Quang Tuan Le; Johan Åkerman; Erik Wahlström; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; perpendicular magnetic anisotropy; tilted-polarizer; spintronics; STT; MTJ; pseudospin-valve; STO; ST-FMR; magnonics; magnetic droplet; droplet nucleation; droplet annihilation; vinkelrät magnetisk anisotropi; lutande polarisator; spinntronik; STT; MTJ; pseudospinnventil; STO; ST-FMR; magnonics; magnetisk droppe; nukleering av droppe; anihilering av droppe.; Physics; Fysik;

   Abstract : Spin-torque transfer (STT) effects have brought spintronics ever closer to practical electronic applications, such as MRAM and active broadband microwave spin-torque oscillator (STO), and have emerged as an increasingly attractive field of research in spin dynamics. Utilizing materials with perpendicular magnetic anisotropy (PMA) in such applications offers several great advantages such as low-current, low-field operation combined with high thermal stability. READ MORE

5. 8. Linear, Non-Linear, and Synchronizing Spin Wave Modes in Spin Hall Nano-Oscillators

   Author : Hamid Mazraati; Johan Åkerman; Dario Arena; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; spin Hall effect; spin Hall nano-oscillators; threshold current; microwave; spin wave; synchronization; Fysik; Physics;

   Abstract : Spin Hall nano-oscillators (SHNOs) are nanoscale spintronic devices that generate microwave signals with highly tunable frequency. This thesis focuses on improving the signal quality of nanoconstriction-based SHNOs and also on developing a better understanding of their magnetization dynamics. READ MORE

6. 9. Spin valves and spin-torque oscillators with perpendicualr magnetic anisotropy

   Author : Seyed Majid Mohseni Armaki; Johan Åkerman; Andrew Kent; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spin torque oscillator; perpendicular magnetic anisotropy; SRA - ICT; SRA - Informations- och kommunikationsteknik;

   Abstract : Researches in spintronics, especially those remarkably classified in the current induced spin-transfer torque (STT) framework, circumvent challenges with different materials and geometries. Perpendicular magnetic anisotropy (PMA) materials are showing capability of holding promise to be employed in STT based spintronics elements, e.g. READ MORE

7. 10. Magnetoresistance and Space : Micro- and Nanofeature Sensors Designed, Manufactured and Evaluated for Space Magnetic Field Investigations

   Author : Anders Persson; Hugo Nguyen; Greger Thornell; Johan Åkerman; Uppsala universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tunneling Magnetoresistance; Planar Hall effect; Magnetic tunnel junction; Magnetometer; Materials science; Teknisk materialvetenskap; Engineering physics; Teknisk fysik; Teknisk fysik med inriktning mot mikrosystemteknik; Engineering Science with specialization in Microsystems Technology;

   Abstract : In recent years, the interest for miniaturization of spaceborne instruments and subsystems has increased steadily, as this enables development of small and lightweight satellite classes as well as more versatile payloads on traditional spacecraft. In essence, this thesis work is an investigation of the applicability of magnetoresistive technology to a magnetometer intended for space. READ MORE