Manipulation by exchange coupling in layered magnetic structures

Abstract

Exchange coupling in magnetic heterostructures can be modified via introduction of additional magnetic spacer layers at the interfaces. The magnetic characteristics and the spacer layer thickness determine the functional properties of the whole system. We show that the hysteresis loop area of trilayer spring magnets with two different soft magnetic layers (s1, s2) and one hard magnetic layer (h) with the sequence s1/s2/h can be increased as compared to both bilayer structures s1/h and s2/h with the same total thickness of the soft layers and for definite thickness ratios of the soft layers and their sequences. For ferrimagnetic spin valves, the perpendicular exchange bias effect can be tuned via the thickness of non-magnetic spacer layers at the interface, which determine the exchange coupling between ferrimagnets. A simple quasi one-dimensional phenomenological model is able to describe the magnetic hysteresis of even complex layered structures and to predict optimal geometrical and magnetic parameters of such heterostructures.

Enhanced remanence and (BH)max of BaFe12O19/CoFe2O4 composite ceramics prepared by the microwave sintering method

“…The magnetic properties of the composite magnets are highly sensitive to grain size, microstructure, distribution of the hard and soft phases and impurity [7]. Nowadays, many researchers pay much attention to the researches of ferrite composite powders including SrFe 12 [11].…”

Tailoring Spin-Wave Channels in a Reconfigurable Artificial Spin Ice

“…In particular, the charge ice, which has been demonstrated to be flexibly reconfigurable using global magnetic fields, can allow for switching between distinctly different spin wave propagation directions as the ice is toggled between Type I and Type II magnetic states. The experimental realization of the spin ice-underlayer system depends in practical terms on achieving a weak exchange bias on the underlayer [42][43][44] , and a reduced exchange coupling between the islands of the artificial spin ice and the underlayer 45,46 .…”

Fabrication and Magnetic Properties of Sintered SrFe\(_{12}\)O\(_{19}\)-NiFe\(_{2}\)O\(_{4}\) Nanocomposites

“…In recent years, nanocomposite magnets have attracted considerable attentions due to their potential applications in microwave devices [1], high-density magnetic recording [2], electronic devices and magnetofluid medicine [3]. Theoretically, by combining high magnetic anisotropy of a magnetically hard phase and the high saturation magnetization of magnetically soft phase, exchange-coupled composite permanent magnets can enhanced magnetic properties of the ferrites [4]. The hexagonal ferrites have high coercivity, large anisotropy field [5] and the spinel ferrites have high saturation at room temperature [4].…”

“…Theoretically, by combining high magnetic anisotropy of a magnetically hard phase and the high saturation magnetization of magnetically soft phase, exchange-coupled composite permanent magnets can enhanced magnetic properties of the ferrites [4]. The hexagonal ferrites have high coercivity, large anisotropy field [5] and the spinel ferrites have high saturation at room temperature [4]. They both have good mechanical, chemical stability and high microwave magnetic loss [4,7].…”

“…The hexagonal ferrites have high coercivity, large anisotropy field [5] and the spinel ferrites have high saturation at room temperature [4]. They both have good mechanical, chemical stability and high microwave magnetic loss [4,7]. Recently, many researchers have paid much attention in studies of ferrite composite powders including hexagonal and spinel ferrites.…”