Free tuning of exchange bias via resettable alignment of antiferromagnetic Néel axes using mechanical vibrations. (15th May 2021)

• Record Type: Journal Article
• Authors: Kim, Hyun-Joong; Yoon, Seongsoo; Ha, Jae-Hyun; Choi, Won-Chang; Hong, Jung-Il
• Is Part Of: Acta materialia. Volume 210(2021)
• Publication Date: 2021-05-15
• Subjects: Exchange bias -- Magnetic anisotropy -- Antiferromagnet -- Piezoelectric strain -- Mechanical vibration; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2021.116821
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Absence of net magnetization in antiferromagnet (AFM) renders magnetic anisotropy of AFM firmly robust against external magnetic field. Therefore, uniaxial realignment of spin structure in AFM requires the field-cooling procedure, which heats AFM to above Néel temperature overcoming the existing anisotropy followed by cooling in a magnetic field to reinstate its anisotropy. Ferromagnet (FM) coupled to the uniaxially aligned AFM spins exhibits unidirectional anisotropy, which is conventionally reflected in the exchange bias effect along the cooling-field direction. Here, we report that alternating mechanical vibrations with relatively low frequencies in the range of few kHz can substitute the inconvenient heating step in the conventionally well-known field-cooling process for the spin alignment of AFM. Mechanical vibration and external magnetic field have been applied simultaneously to AFM IrMn3 /FM Co or CoFeB bilayers deposited on Pb(Mg1/3 Nb2/3 )O3 -PbZrO3 -PbTiO3 (PMN-PZT) piezoelectric single-crystalline substrate in an ambient temperature. Exchange bias of the bilayers can arbitrarily be set along a desired direction as determined by the applied magnetic field. The simple technique without a heating step enables local control of exchange bias effect at selected regions only within complex microdevice structures. Furthermore, the capability of repeated post-readjustment of exchange bias effect in various directions and magnitudes would promote wider integrations of exchange-biased system in novel magnetic devices. Graphical abstract: Image, graphical abstract