LECTURE ABSTRACT

 

WITH MAGNETIC METALLIC NANOSTRUCTURES

 

A.B. Rinkevich, L.N. Romashev, V.V.Ustinov

Institute of Metal Physics Ural Division of RAS

18 S.Kovalevskaya Str., Ekaterinburg, 620041, Russia

e-mail: rin@imp.uran.ru

 

Microwave properties of magnetic metallic nanostructures with giant magnetoresistive effect are reported about. Two main physical reasons cause microwave variations, namely the microwave analog of giant magnetoimpedance effect and ferromagnetic resonance [1,2]. If the fields are lower than magnetic saturation field, the field dependence of the transmission coefficient is mostly due to the first mechanism. This dependence looks like the DC magnetoresistive one. There is approximately one-to-one correspondence between microwave and DC relative variations. The second mechanism is observed only under perpendicular pumping. The essential resonance variations are observed only at the frequencies of millimeter waveband. The resonance amplitude is the highest in those samples where the resonance falls in the magnetically saturated state of the nanostructure. Methods of microwave magnetoresistive effect measurement are presented. The experiments in the "current perpendicular-to-plane” geometry are specially considered, and the experiments carried out in the millimeter waveband are presented. The peculiarities of the joint observation of ferromagnetic resonance and microwave magnetoresistive effect are specified. The propagation of electromagnetic waves in a rectangular waveguide containing a gyrotropic plate made of a metallic-film nanostructure was studied. Changes in the propagation constant were calculated for the cases of in-plane and normal magnetizations. In the region of frequencies and fields that is far away from the condition of ferromagnetic resonance, the changes in the absolute value of the transmission coefficient are proportional to that in resistance. Expressions were obtained for the changes in complex reflection and transmission coefficients.

 

 

Metallic nanostructures and their structure and preparation.

Exchange interaction and giant magnetoresistive effect.

Magnetic resonance in nanostructures.

Reflection and penetration of high frequency electromagnetic waves through metallic nanostructures.

Penetration in a wide frequency interval.

Realization of "current-perpendicular-to-plane" geometry at microwaves.

Measurement of giant magnetoresistive effect at the traveling waves.

Application of metallic nanostructures in nanoelectronics and spintronics.

 

Microwave methods give a unique opportunity to estimate the dynamic and relaxation parameters of nanostructures as well to study the spin - dependent transport. Application of the metallic magnetic nanostructures in microwave electronics is also discussed.

 

 

[1] J.Krebs, P.Lubitz, A.Chaiken, and G. A.Prinz, "Magnetoresistance origin for nonresonant microwave absorption in antiferromagnetically coupled epitaxial Fe/Cr/Fe(001) sandwiches”, J. Appl. Phys., vol.6, No.8, Part II, pp.4795-4797, 1991

 

[2] A.B.Rinkevich, L.N.Romashev, V.V.Ustinov, E.A.Kuznetsov, High frequency properties of magnetic multilayers, JMMM, vol. 254-255C , pp. 603-607, 2003