Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 37: Spin Torque and Spin Excitations I

MA 37.3: Vortrag

Donnerstag, 3. April 2014, 10:00–10:15, HSZ 401

Topologically Protected Magnetic Helix for All-Spin-Based Applications — •Elena Vedmedenko and David Altwein — Universität Hamburg, Deutschland

The recent years have witnessed an emergence of the field of all-spin-based devices without any flow of charge. An ultimate goal of this scientific direction is the realization of full spectrum of spin-based networks like in modern electronics. The concepts of energy storing elements, indispensable for those networks, are so far lacking. Analyzing analytically the size dependent properties of magnetic chains that are coupled via either exchange or long-range dipolar or Ruderman-Kittel-Kasuya-Yosida interactions, we discover a particularly simple law: magnetic configurations corresponding to helices with integer number of twists, that are commensurate with the chain's length, are energetically stable. With increasing number of twists the energy of the helix increases but, once achieved, remains stable at small temperatures. The higher energy levels can be reached by rotating one of the chain ends like the winding up of spring driven clocks. This finding, supported by simulations and an experimentally benchmarked model, shows that boundaries can topologically stabilize structures that are not stable otherwise. On that basis an energy storing element that uses spin at every stage of its operation is proposed [1].

[1] E. Y. Vedmedenko, D. Altwein, Phys. Rev. Lett., accepted (2013).