Nanoscale magnetic ratchets based on shape anisotropy. (19th January 2017)

• Record Type: Journal Article
• Authors: Cui, Jizhai; Keller, Scott M; Liang, Cheng-Yen; Carman, Gregory P; Lynch, Christopher S
• Is Part Of: Nanotechnology. Volume 28:Number 8(2017)
• Publication Date: 2017-01-19
• Subjects: magnetic shape anisotropy -- nanomagnetics -- magnetoelectrics -- multiferroics; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/1361-6528/aa56d4
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: Controlling magnetization using piezoelectric strain through the magnetoelectric effect offers several orders of magnitude reduction in energy consumption for spintronic applications. However strain is a uniaxial effect and, unlike directional magnetic field or spin-polarized current, cannot induce a full 180° reorientation of the magnetization vector when acting alone. We have engineered novel 'peanut' and 'cat-eye' shaped nanomagnets on piezoelectric substrates that undergo repeated deterministic 180° magnetization rotations in response to individual electric-field-induced strain pulses by breaking the uniaxial symmetry using shape anisotropy. This behavior can be likened to a magnetic ratchet, advancing magnetization clockwise with each piezostrain trigger. The results were validated using micromagnetics implemented in a multiphysics finite elements code to simulate the engineered spatial and temporal magnetic behavior. The engineering principles start from a target device function and proceed to the identification of shapes that produce the desired function. This approach opens a broad design space for next generation magnetoelectric spintronic devices.